What Is The Protruded Painful Bone In My Shoulders?

On the top of my left shoulder, about 3/4 of the way out (from my neck to my shoulder) there is a small round bone that sticks up. Both shoulders have the same bone protruding. When I touch the bone on my left shoulder it is very tender and I also get shoulder pain. I am not limited in my ROM. I am extremely active and exercise regularly 6 days a week. It does not feel like a tear and there are no popping noises. I am able to do pushups and Yoga with no pain to this area. I did a pull-up last night to test it out and again, no pain. It is painful when the arm feels "jambed" though.