i clicked on this thread because i can definitely relate. i have the same problem. i was going to ask if you use any other drugs besides weed.
you said you use opiates too. i would say that is probably the cause of it. not the weed.
i started having this problem around the time of my heavy heavy drug use, about 5 years ago. when i was abusing methadone, my hands would become numb, tingly, like they're asleep...it become a real problem and i knew something wasn't right. so i stopped with the methadone. i was taking massive amounts of it...ofcourse i went onto other drugs. but i still have this issue with my hands. never got it checked out by my doctor, but its just my guess and opinion that its from drug use.