I hurt my neck/shoulder/back a long time ago snowboarding and now its very prone to injury. Whenever it flares up I find the best drugs to fix it are NSAID's, in particular the best I find is ibuprofen because it reduces the infammation that causes the pain in the first place. There are other anti-inflammatories but Ibuprofen is the best IME.. That, and lots of heat on the affected area.
Nurofen or Nurofen+ with codeine is what I take and it usually clears up in a few days.