Just be careful not to let it go into your ass muscles from over compensating. I did just this around New Years and now my piriformis group has swollen up. Which is painful in its own (especially because its near impossible to stretch those muscles to heal them up), but also because they then place pressure on the sciatic nerve at the base of the spine. When that happens, the entire back of the leg either feels likes its cramped or on fire. Not pleasant. So, moral of the story is, if you ever hurt your lower back-- take it easy and slow.