Hi - I Started Having Severe Neck Pain (unable To

Hi - I started having severe neck pain (unable to turn side to side without pain) within hours of taking Phentermine. I have taken this drug before but never experienced this. I know it was not caused by sleeping wrong because it started in the afternoon. My doctor's nurse said this is not listed as a side affect of the drug, but I've seen many posts from people with the same issue. I do not want to stop taking the drug because I need to lose weight. My question is what can I do to counteract this pain?