@jewhite seems strange if you've been on Tamoxifen that long that these new symptoms would be presenting now and would most likely not be. Id check with your GP and also your Oncologist. I was on it for 4 yrs with no side effects not that i noticed but was pre menopausal, that seems to make a big difference. Chemo impacted so very many things for me in side effects and recovery and ongoing symptoms. Chemo brain for instance is very real but I am learning that it really does dissipate, my brain after 20 months has finally kicked back into gear. So definitely get it checked out! Could well be something completely different. hugs x