I know I'm 22, but could this be heart problems ??

Okay so I recently just went to the doctor for constant chest and back pain. She diagnosed me with a stomach ulcer ... because I've been showing a lot of symptoms of that.. but I still can't shake this feeling of it being heart related. I have been under A LOT of tension and stress this past year.. and I know that has affected my body , but it's 7am, I woke up at 6 am having shortness of breath and lights chest pain, and my heart was beating fast.... I shouldn't have googled , but I did .. and it only made it worse. Has anyone dealt with this before ? I'm really freaking out that I'm having some sort of heart failure... but literally everyone thinks I'm crazy because I'm so young.