ice-is-scary, having had (and still having) shoulder problems, you definitely want to go to the doctor. There are many possibilities for your problem, though my experiences are similiar.
You may have tendonitis, or your shoulder may be loose in the socket. This could require an injection, rest/advil, physical therapy, or a combination. In some cases, surgery is needed.
Since you mentioned incline presses and shoulder exercises/lifts - it is important to realize that the type of problems you may have might require you to do exercises that stress the muscle in ways typical gym exercises don't. Things like shoulder presses, side raises, arnold presses, etc. mostly deal with the deltoid muscle group, whereas shoulder problems could easily involve different muscles not worked by that type of exercise.