What Causes A Feel Of Crawling And Tingling Sensation In Abdomen?

Hi, I keep feeling like something is crawling inside the left side of my belly & it has a tingling sensation that I can feel all the way through my back on the same left side. It's always in the same area. I have no pain with it ever. This has been going on for about 3 weeks now & it happens on & off and at no specific time that I can notice. It feels really creepy. It do remind me of when i was pregnant with my children, but there is absolutely no way I can be pregnant because I have been celibate for 11 years. I have never experienced this before in my entire life. Have you heard of this & do you know what it could possibly be?