Drs say it takes a few months for your body to adjust to Tamoxifen. If you are still the same talk to your Oncologist. You can always try a different brand. There are quite a few generic brands that use a different base but still contain the same main ingredient. Some people have found a change is what relieves symptoms.
Must say my aching legs are ok now but I'm still always hot! Try and exercise and eat well and that helps too. I take my tabs at night.
Your symptoms sound typical of menopause. Not sure how old you are but Cancer treatments may induce menopause early if you are under 50.
Good luck! You are not alone.
Diane