Intermittent tooth pain?

I've been getting tooth pain on and off on the rear part of my lower right side the past couple of weeks. It doesn't happen every day. The pain comes and goes and usually doesn't last for more than 40 minutes. Sometimes it goes away within 2-5 minutes. Sometimes it can occur several times a day. I noticed brushing when I feel pain helps to get  rid of it or lessen it.  

I would say the level of pain is a 3 out of 10. This pain feels like it's in my gums rather than the surface of the teeth itself. I haven't noticed any sensitivity or pain when I eat, drink or press down on my teeth. Earlier today I noticed I had also started to feel it in the front part of my lower right side.