pain
"I was born with arthritis and have been on many of the narcotic based drugs in my 20  years of being treated.  I noticed someone saying that methadone makes them feel tired when they sit.  I know that is a normal side effect but I urge ALL men that are taking ANY narcotic pain medication to get your testosterone checked!  Narcotics lower the level of testoserone and that makes you feel very tired.  I was feeling very tired all the time and didn't really have any get-up-and-go and would have "Hot Flashes."  I got my levels checked and my testosterone was almost at female levels.  Now I get testosterone shots and feel much better.  If you are on medicines long term, get your levels checked!"