Letrezole

After having a double mastectomy in September of last year I had chemotherapy until 4 months ago. Felt pretty good through chemo , just chemo brain for a few days after and fatigued.I have been taking Letrezole 2.5mg daily for 4 months now . Have awful muscle and bone aches and night sweats . Any one feel the same and does it wear off after time ,supposed to take this for 10 years .