Methadone Hydrochloride and shoulders

i am having headace's extreme constipation, it isnt taking my pains away like it is suppose to i take 10mg a day is it suppose to do this i hurt all the time now what should i do i have multi instibility in my shoulders and neck is this the right durg for me please let me know

i was setting on my computer the other night got up to go upstairs half why there i got out of breath and my heart started to throbb like it was comming out of my chest and then got a burning down my shoulders and the back of my neck just like someone was burning me i am on methadone 10mg 6 times aday i only weigh 117 and man it mess me up but helps the pain great but i thought i was dying im wondering if i should stay on it been on it for a month anybody else had this let me know what to do