I do my chest workout once a week. I cycle between Flat, Decline and Incline Bench press every week.. so for week 1, I do flat. For week 2, I do Decline and week 3, I do Incline. I repeat that cycle week 4, 5 and 6.. and so on.

I have been consistantly doing this for over a year. Lately, I have been having shoulder pain every time I do flat bench barbell press.. my sholders seem to fatigue VERY quickly and they feel sore and interrupts me from continuing bench. On that same session, if I switch over to Dumbell Flat Bench using the same weight I did with Barbell Flat Bench, I don't feel that shoulder pain. I don't feel that pain when I do Decline/Incline Barbell Bench presses either. It only seems to happen with Flat Bench Barbell Presses.

I feel as if the way the Barbell puts pressure on my shoulders when I'm on flat is what's causing the problem.

I've asked some veteran lifters at the gym and they think I'm doing more weight than my shoulders can handle, but I disagree. I don't seem to have shoulder issues when I switch it to flat dumbell bench press or decline barbell bench press using the same weight.

Any insight into this is appreciated. Is it OK to give up on Flat Barbell Bench Press and substitute it with Decline Barbell Bench Press?