Started taking Levothyroxine 100 3 weeks ago, for last week I'm i...

I've been on the generic levothyroxine 125mcg for over a year, I keep telling my doctor its not the same as synthroid. The joint pain is terrible my shoulders are the worse, I've gained weight and I've been pretty active my whole life. Is anyone else experincing this either with the generic or synthroid. I now a company in mexico sandoz that was making the levothyroxine is no longer the company now is Mylan but I'm having the same symptoms sick and tired of it I'm only 47 and had an active lifestyle.

i started taking 75mg levothyroxine 5 weeks ago, i fell fantastic for the first couple of weeks, now for the past week i can hardly walk,raise my arms, the pain in my shoulders/upper arm, thighs and knees is unbearable....i cannot hardly walk. I went to doctors and he said i had a virus !