Why Am I Experiencing Pain In Shoulder During Orgasm?
During intercourse, there is not doubt that this places an increased "stress" on the heart. Given your age, history and the symptoms that are associated with the "stress" of intercourse and orgasm, it might be appropriate to consider that the pain in your shoulder is actually related to something else, like your heart.
Pain can be 'referred' to areas of the body unrelated to the source of the pain. Heart pain is typically referred to the left shoulder, but it is theoretically possible that it could be referred to the right as well. Avoid further intercourse and call your doctor tomorrow and ask for a visit to discuss whether there are any concerns about your heart in this case, especially given your underlying heart disease.
I hope that this helps. Please ask if you have followup questions.
I am sorry that I am not of more help. Perhpas the opinion for a different type of specialist (Neurology) would provide an answer to this question. I would schedule a visit in person with such a specialist.
Good luck.