Hi yes different brands can have differnet side effects, thats what I've found basically the side effects we all suffer are not universal as with our cancers we are all different and its just a case of trying the different brands out and finding which ones are the best. My side effects (please note you might not have the same SE not everyone does) include something similar to thrush a sort of constant side effect no matter what brand I use, really painful joint pain in both ankles and wrists, cramping pain in lower legs especially at night as well as restless leg syndrome, weight gain its been steadily going up and up since I started 2 years ago, I've gone from a size 8 to a size 18!!! in a little under 2 years my onc agrees its the tamoxifen and its looks like they might be taking me off of it and trying me on something else, the only problem is that I'm still peri-menopausal so they wont change it until I'm through.
Hope you find some respite from your side effects and best wishes xx