If you are taking Methadone for the high/good feelings it gave you, then you are taking it for the wrong reasons completely.
Typically, when you are put on a long term
pain medication, your body acclimates to it, and you stop experiencing the side effects that someone new to the medication would have for a short time. It is called tolerance. I was on methadone for severe back pain and I never, ever got "high" or felt good, happy or whatever you want to call it from it.