leg pain

hi all i am back at work but feeling a bit tired at times. i have been taking arimidex for about 6mths and had little side effects. however i am noticing leg pain and cramping in lags worstening over last few months. i also have a feeling of muscle weakness in my legs . i am told this is a side effect of arimidex does anyone else have this problem. its not that bad that i have to take pain killers but it makes me want to sit down and do nothing .