What Causes Elevated Heart Rate And Coughing?

I m a 19 year old male, 163 pounds 6 0 . I take dexedrine 5mg 2x daily(for adhd) and metoprolol half a 25mg pill at night usually(to lower anxiety and hart rate). I went to the cardiologist last year because I thought I had SVT and I had several EKG s, 1 ECG, a 24hr holter monitor and although my heart rate rose up to 168bpm that day, without exercise, the doctor just told me I was an anxious person with very slight mitral valve regurgitation that needed to be on anxiety meds, so I got diagnosed with panic disorder and put on klonopin. I no longer take them as i ve switched to the Tropol(lowers my heart rate & palpitations which is where the anxiety would stem from but that wasn t taken into accreditation which leaves me to believe even more I had a misdiagnosis). I do notice small things when it comes to health issues but i ve noticed now that i m back on my adhd medicine my heart rate tends to always be over/around the 100bpm range resting, and with exercise can get up to 205bpm(that happens anyway with exercise though if I don t take my metoprolol). I ve developed a slight cough that I can t get rid of, I can always see my heart beating out of my chest, sometimes I get a choking feeling or I can feel my pulse in my neck, and my stomach is a little bigger. I go running or biking at least 2 times a week and I eat healthy, so this leaves me to believe I am either psyching myself out or I have a pre-existing heart condition that the doctors have all shrugged off and I should not be taking dexedrine. However I do smoke around 3 cigarettes a day sometimes less. And if that is the case i m really afraid I have heart damage or something with these new symptoms. I don t have insurance as of last month too so I can t go back to the doctor for the time being. I need to know what I should do and what I may or may not have.