OUCH! It could be nerve. I get that in my ribs but it is lower than my breast area. It's my ever loving MS hug.
Are you close to your period? Can you feel any lumps? I'm "lumpy" and have had similar pain when one of the cysts acts up. It's not a comfortable feeling.
Since it kept you up at night and you aren't too sure what it is, I would give your dr a call. Maybe start by calling your PCP and then go from there.
Check in with us and let us know how you are doing.