Written by the Phoenix Rehab physiotherapy team.Clinically reviewed by Louise Yow, Principal Physiotherapist & Director, AHPC A1300363H.Last reviewed 2 October 2026.
If you felt a pop lowering a heavy bench press and the front of your armpit now looks flatter on one side, see a doctor this week. That combination usually means the pec major tendon has come off the arm bone, and a complete tendon tear is a surgical decision with a time window. A strain in the muscle itself is far more common. It hurts more than it looks, and it is managed without surgery.
Chest muscle pain after the gym: strain, tear or something else?
Most chest muscle pain after training is one of three things. Soreness across both sides a day or two after a hard workout is ordinary training soreness and fades in a few days. Pain on one side that started during a set, hurts when you press or bring the arm across your body, and is tender to press, is usually a pec strain. A pop, bruising and a changed armpit fold point to a tendon tear. Chest pain that comes with breathlessness, sweating or pain into the jaw or arm is none of these. Call 995.
Strain or tear: how to tell
You cannot be certain from the outside, but these signs separate the two most of the time.
| Sign | Muscle strain | Tendon tear |
|---|---|---|
| The moment | A pull or tightness, often late in a set | A pop or tearing feeling, usually lowering a heavy bar |
| Bruising | Little or none | Bruising that spreads down the inside of the upper arm over a few days |
| The front of the armpit | Looks the same as the other side | The fold looks thin or flat, and the muscle bunches toward the chest when you press your palms together |
| Strength | Sore, but it works | Clearly weak bringing the arm across the body or pushing |
Only imaging settles it. A doctor orders the ultrasound or MRI. We do not, and if your strength and the shape of the fold point toward a tear when we test you, we will send you to get one before we do anything else.
Why timing matters with a full tear
Complete tears of the pec major tendon are usually repaired surgically, and repairs done in the first weeks after the injury tend to do better than repairs done months later, after the tendon has pulled back and scarred (Bak et al. 2000; ElMaraghy and Devereaux 2012). That deadline belongs to the tendon, not to us. If this sounds like you, an orthopedic surgeon is your next appointment, and your GP or an emergency department can get you there.
Who it happens to
Mostly men between about 20 and 40, mostly in the gym, and mostly on the way down in a bench press, when the muscle is stretched under the heaviest load it will see that day. Falls onto an outstretched arm, rugby tackles and judo throws account for most of the rest.
How long does a pec strain take to heal?
A strain in the muscle belly usually settles over three to eight weeks, depending on how much of the muscle is involved. Rest settles the pain. It does not put the strength back, and the strength is what the next heavy set asks for. These are the stages we work through:
- Stage 1, Calm & Protect: pressing stops, everyday movement continues, and we find the range that does not provoke it.
- Stage 2, Move & Mobilize: the arm back across the body and overhead, so the muscle is not left short.
- Stage 3, Rebuild & Strengthen: floor press, push-up progressions and cable work, measured against the other side.
- Stage 4, Return & Perform: the bench press comes back on a written ladder of weight and sets, not on how it feels that morning.
Pec stretches: when they help, and when to wait
A gentle pec stretch belongs in Stage 2 of a strain, once pressing on the spot no longer makes you wince. The doorway stretch is the simplest: forearm flat on the door frame with the elbow at shoulder height, then step through until you feel a stretch across the front of the chest, not a pull at one spot. Hold about 30 seconds and breathe. Stretching hard in the first days of a strain, or at any point after a tendon repair before your surgeon allows it, works against the healing tissue.
What happens after a repair
After surgery the arm is protected in a sling for about four to six weeks. Range comes back first, then light strengthening from around eight to twelve weeks. Heavy pressing usually waits until about six months, and your surgeon decides when. See physiotherapy after surgery.
When to see a doctor first
Call 995 if chest pain comes with breathlessness, sweating or pain spreading into the jaw or arm. That is not a pec injury until a doctor says it is. See a doctor this week if you felt a pop and now have bruising down the arm or a changed armpit fold. See a doctor soon if you have numbness or tingling down the arm.
Where are you with this right now?
1. It is settling on its own
If it eases week by week and light pressing no longer hurts, you are on the right road. Build the weight back gradually. You do not need us for this, and we would rather say so.
2. It has stopped improving
Six weeks on, push-ups are fine but the first heavy set still pulls at the same spot. You have quietly swapped the bench for machines and stopped going near your old numbers. That is a strength problem rest will not fix, and it can be measured against the other side. Every first visit is one 45-minute Assessment & Treatment, $230, nett, no GST. If it has been months, the Stalled Recovery Review is three appointments over three weeks with the same therapist, $690.
3. You have had surgery, or you have a date
A pec major repair has a shape: protected weeks, then range, then load. See physiotherapy after surgery. All of it runs on the four stages of the Phoenix Recovery Protocol.
Related reading
Sources: Bak K, Cameron EA, Henderson IJ. Rupture of the pectoralis major: a meta-analysis of 112 cases. Knee Surg Sports Traumatol Arthrosc. 2000;8(2):113-119. ElMaraghy AW, Devereaux MW. A systematic review and comprehensive classification of pectoralis major tears. J Shoulder Elbow Surg. 2012;21(3):412-422.
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