Name this weird pain

moosegal

This morning before I got in the shower, I was lounging in bed for a bit and noticed it felt like I had a bubble of something in my abdominal area (gas?). It wasn't too bothersome or painful, just something I noticed.

Got up and hopped in the shower, and (sorry) started feeling like it would be really great if I could just pass gas to relieve some of the pressure. Didn't really happen though.

By the time I got out of the shower, I was having this horrible cramping pain in my lower back, so I crawled back in bed. The only thing that helped it subside was having DH massage the area where your back love handle sort of meets your buttocks, if that makes sense. 

It went away and I was able to get up and finish getting ready, and the pain hasn't come back, but I have zero clue what could have caused it. Any ideas? I might call my DR for peace of mind, but I don't know if my description really does it justice or explains it adequately.