Could be form, although for some people overhead pressing is just not agreeable with their joints. Personally I do overhead pressing movements once every two weeks, if I did it every week I'd be in trouble.
I had the same problem, wasn't angeling my elbows right when benching. Usually felt the pain while doing rows or overhead press, when the pain shot in I was unable to complete the sets. Even if I threw off a couple of kilos I'd still struggle.
However, since improving my form on the bench it hasn't been a problem. Think there was a video posted a few pages back which helped me.