Recently I have been experiencing a sharp sternum pain when doing push ups. Normally, I can do about 50 push ups in one set, but recently at push up number 42 the sternum pain becomes so strong that I am unable to go passed 42. My push up form is proper (arms being shoulders width apart, and proper speed lowering and lifting).
Age - 20
Weight - 115lbs
Height - 5'8"
I am not taking any supplements or doing any other exercise/workout besides push ups and sit ups.
Maybe my body is starting to grow in the chest area which is causing the problems? I am not sure what to do. I rested for 2 days before attempting to reach 50 push ups again, however I got stuck at 42 again. Should I just do like more sets of less numbers (like 40, 22, 20, 15 or something)? Any tips appreciated.
Thanks in advance.