I Have A Shoulder Injury Don't Know How I Did

i have a shoulder injury don't know how i did it but it has been going on since last september, i have been precribed naproxen 500 twice a day for 2 weeks it does not seem to make much difference to the pain especially at night , i can't sleep and when i get up in the morning are very fatigued,is there anything else i can take, i have tried heat bags but of course they go cold after a while, i am waiting to get a mir scan,to see what is going on in my shoulder.please advise.
regrards D Barker