Hi Maryden,
I am really sorry to hear you have been experiencing back pain. There are a lot of users who are on tamoxifen and I am sure they will be along to offer their support soon. You may want to take a look at our page on tamoxifen.
In the meantime please do call our helpline on 0808 800 6000 who will be able to talk to you about the pain you are feeling and offer a friendly ear. The opening hours are below.
Monday-Friday, 9am-5pm
Late opening Wednesday 9am-7pm
Saturday, 9am-1pm
Best wishes,
Lizzy