I've been on Tamoxifen for 12 months now. When I was first diagnosed, I read plenty of nightmare stories about Taxomifen on these forums which really, really upset me. As RevCat says, people will always post about the negative stuff and less so about the good stuff. This does give an unbalanced view. Also, many people do not get bad side effects so remember this.
I am 44 years old. My symptoms 12 months on is that I occasionally feel a bit warm. Easily resolved by removing a blanket off the bed and such a minor thing to put up with. I also have more mobile joints and have had no joint problems. I am pre-menopausal and Taxomifen has a varied effect on your periods. For me, they stayed regular, got heavier for a day but were of shorter duration. Continuing your periods does not mean the Tamoxifen is not working.
The 'temperature fluctuations' started 21 days after starting Tamoxifen, and to be honest they were difficult to handle with little sleep for several weeks. Most of this in hindsight was made worse by me getting upset about the hot flashes. Once I stopped panicking about feeling hot, things settled down quickly and got better over time to the stage I am now. I get warm days maybe several times a month, but that's it.
If you do get symptoms with Taxomifen, do persist with the knowledge most symptoms settle down with a bit of time.
I can't offer advice on the MX as I had a lumpectomy.
Good luck with your journey ahead.