My heart sometimes feels like it beats fast and then it returns to normal but it's only really quick. is this normal, should i be concern, i have no heart issues and i'm not overweight. been noticing it more and more lately?

Very difficult to determine if you have a cardiac arrhythmia (irregular heartbeat) by how you feel. If this is a real concern, see a doctor. He/she can run an EKG and, if OK, reassure you. If truly irregular, you will need a more complete work-up by a Cardiologist

it may be short episodes of supraventricular tachycardia I recommend seeing your primary care doctor and asking for a referral for an adult cardiologist