I'm having pain right under my chest between my stomach and chest really all I had for breakfast was cereal with almond milk and a banana?

Difficult to know. Pending your overall health, medications, prior illnesses and any known digestive issues, one would be concerned with these symptoms. Can't say i know where, exactly, you are hurting and other symptoms but would recommend getting checked out. Ulcers? Gallbladder dz? Pancreatitis? Allergy to foods? Bad reflux/gerd/heartburn? Many things to consider. Get seen and checked out!
Need more details. How old are you what other medical problems do you have what meds do you take what precipitates the discomfort? Is it related to activity? How long does it last what does it feel like what other symptoms?