I am sorry for the lack of information that I have given.
I have been playing the harp since I was ten years old so for about 13 years. I studied privately for 8 of those years with one teacher and then with another private teacher in college. My harp is a Lyon and Healy Style 85 Petit. I was always taught to have a balance between me and the harp so that the weight doesn’t rest on me. I’m pretty certain that is not the cause. This pain in my shoulder has been a recent development in the last year or so. As for bench height would I be sitting too low or too high?
Tayce, you mentioned holding your arm up using the muscles under your shoulder blade. Could you explain that more?
I will say that I have performed and studied privately for many years but this is my first experience speaking with as many experienced harpists as this forum merits and while that is a great experience, it is also an intimidating one. I appreciate all of your feedback. Thank you so much for looking at this problem with me.