Yes i think that muscle tensness could have something to do with your anxiety levels. I know then when i'm feeling really anxious my muscles tense up and almost feel out of control (feeling really jumpy). I've never tried any creams before, but sometimes getting in a good stretch can help. I've gotten into the habbit of stretching before i go to bed and that really helps with sleeping. Backaches could also be a result of muscle tension so stretching might help that as well.
Hope this works
Jacq