Back injury - what exercises can I do?

Sweeterescape

I believe I pulled the muscle where my glute meets my lower back. I've rested as much as I can the last few days (I have to walk a mile each way to the train station and other walking during the day) but it's still not better.

I'd really like to keep fit and burn some calories but I don't want to put stress on the muscle. Any exercises I could do?

Thanks!