Pain Management requires at least 2 things:
1 - Attitude going into your surgery: Your mindset before the surgery is a crucial part of your post-op experience. Go into your surgery EXPECTING to be successful and victorious. There is a well-worn axiom "If you think you can, you're right! If you think you can't, you're right!. Now choose". Work to be as positive as possible in order to increase your chances of a smooth recovery.
2 - Perspective of alternatives: As uncomfortable as the day after your surgery may be, it's NOTHING compared to the series of painful compromises and surgeries that accompany a long-term weight issue. Choose this recovery over surgery for an amputation down the road (I have seen this in my extended family, so this is no idle threat to our health).
Embrace this as the corrective step needed to reset your health and embrace YOUR future. Keep your eyes on the Long Game.