I’m on letrozole not tamoxifen, but if your oncologist is recommending it, why not try it with as open a mind as possible? You may not have the side effects you fear, and even those with difficult side effects often stay with it because of the potential benefit. You can always stop if the side effects are too bad, no-one can force you to take medication. But as side effects can vary immensely, perhaps you owe it to yourself to try and see what happens in your case, rather than relying entirely on the experience of some others. Best wishes whatever you choose.