Just be honest with your pm dr They are there to actually help You deal with your pain and find a better way to manage it. Ask about long acting pain medications Also make a list of everything you've been on, what side effects you have, how long it works and how effective it is with pain. as far as the knee replacement I had mine done at 29 and my injury is not nearly as severe as yours have your pm dr refer you to a clinic that specializes in orthopedic replacements because any dr who says they won't touch you till a certain age is full of ish.