+1 on the vet sources. Only other thing I can add is that the IM version can be administered sub-q (at least in dogs), so I can't see that being too painful with a 'slin pin. I'd try that first if it was me.
thanks fellas, its gotten so bad i cant even do upright rows without wantin to strangle someone cause of the pain. ive tried every friggin anti imflammatory out there. might just need to operate.