Aromasin question

Hi there

Could you please tell me or advise me? I have been on Tamoxifen for 2 years. I started for 4 months on Arimidex, I had significant discomfort in my bones and joints but I was able to cope with it. I was changed to Tamoxifen because I has some spotting and as I was 46 yrs old it was possible my ovaries maybe switching back on again. I have recently seen my oncologist and as I did not have a return of my periods after all, he is suggesting that I now switch to arimidex. I am an exercise teacher and it is important that I have good flexibility and mobility. My Mother had the same BC as me and it returned after 4 yrs in her bones. she was on Tamoxifen. As I understand it Arimidex can be more affective and can prevent distant cancers as well as localised. Am I correct in assuming that Tamoxifen won't prevent distant cancers only in the breast? Would Aromasin be a better option for me? My cancer was 3cm in size grade 3 and 11 lymph nodes were removed and none of them were involved. I had 6 sessions of FEC and 6 weeks of radiotherapy.

Regards

Vivienne