Wendy, there are many things, I'm told, that one can do for hot flashes.  Tamoxifen is an excellent drug with a long, outstanding history, and there is some evidence that women who experience hot flashes while taking it have less chance of a cancer recurrence. So I hope you keep taking it even though it's hard. 

I would try all the wholistic remedies first.  Eliminate caffeine and alcohol, and try to note what is happening and/or what you're thinking when you get a hot flash.  Add 30 minutes of exercise every day (build up to this from wherever you are).  Consider acupuncture, which has been shown to reduce hot flashes up to 50%, especially those at night.  Some insurance plans do pay for it.

Finally, there are a series of particularly antidepressants that can be used in low doses to combat hot flashes.  Oops, here comes one now!!  Also, there is a medication called gabapentin (Neurontin), which supposedly really work.

Here's me: I exercise 30-90 minutes every day.  I started getting hot flashes during chemo, and I also had my last period during chemo.  I finished chemo eight weeks ago.  I am building up my doses of tamoxifen, now at 1-1/2 tabs.  I get a severe hot flash every 45 minutes or so, night and day.  I feel like I haven't slept for months. 

So -- I'm going to try the Neurontin, and we'll see how it goes.  It's scary to take these powerful medicines, but this is ridiculous.

Good luck!