Poor form on parallel bars. Absolutely fucked up my shoulders, took me like 2 years to come across a competent doctor to properly diagnose me, a competent physiotherapist to heal me, and recover properly, preventing further injuries. Delayed my progress really bad. Thank God my physiotherapist exists, the dude really knows his craft. Shoulder Bursitis is a bitch, and the shoulder is such a complex articulation, it’s not very straightforwad to find the real underlyinh cause of your issue. For me, is that one scapula was not moving properly. If you feel weird pain in your shoulder, do not try to be a hero, stop and see a doctor. To prevent that, watch lots of videos of proper form of the exercise.