Contractions?

So I've been having period like cramps, the pain is about where I'm guessing my ovaries are located. The pain used to only be there for maybe 10 seconds and would go away. I'd have it maybe once every few days or sometimes twice a day depending. If I shifted or rolled over it would go away quicker. It then went away for about 2 weeks. I now have it again and it's stronger pain but its more uncomfortable than anything. Just a sharp pain for like a minute and then it goes away. Is this Braxton hicks or just random pain? Is it the start of labor? How do I know what's a contraction and what's not?