Been noticing some lower chest problems?

So over the past year id say I would randomly start to feel discomfort right under the very top of my rib cage that would only hurt if i bent over or laid on my side. when i walk its fine. im not sure how to explain the pain other than like pressure. any idea what this might be? it hasn't really affected me just pain. im usually just fine the next morning too. i usually notice it every month and a half or so. Should i see a doctor? thanks everyone.