I have been experiencing pain under my left collar bone after doing chin-ups. When I first started doing chin-ups, I did not experience any pain. But after awhile, I feel this sharp pain under my left collar bone when let go of the bar and put my arms back in normal position.

The pain also happens when I lift my left arm all the way up, and relax it back at normal position.

This was 3 months ago. I thought it would be some strain in the muscle or tendons. So I tried doing chin-ups again, just now. After doing 2 sets of 10, I could feel slight pain under my shoulder after that.

Additional info: I do standard chin-ups, both wide grip and normal grip.

It would be great if any of you could give me advice/tips. Thanks a bunch!