Can you tell me how i could diagnose a shoulder injury based on symptoms and not an mri?

Raise your arm up: like you want to answer a question like you did in school. Also you could try to flap your arms up and down like you want to fly. If either of those hurt you have a shoulder injury Obviously this is a generalization, but to know where it hurts exactly takes more specific movements and knowledge base. Also imaging is very helpful when treatments are being planned to address these injuries.