Could Overuse Of Coricidan Cause Chest Tightness, Increased Heart Rate, Palpitations And Hypertension? What Is This Condition?

I m a twenty year old male, and my chest is very tight, along with it being hard to swallow, and take in a deep breath. This just started today, but i have been getting heart palpitations frequently, (at least a series of them every 30 minutes off beat) for around a year, heavy palpitations. My heart always seem to be beating really hard, so hard that i shake, and my neck is almost always twitching, especially if I m in a situation that s prone to raising my heart rate. My blood pressure only seems to be slightly above normal anytime I m at a doctor. Which from my understanding doesn t add up. I m worried that my heart might be enlarged, and almost positive i will have a bad heart in the future. But i would like to know the possibly of having these conditions, and if these add up to a specific heart condition. Also one thing i suspect contributed to it is, when i was 16 i took a 16 count box of Coricidan cold and cough 3 separate times. I was young and stupid, and i regret it. The main ingredient in Coridian is DXM. Which has been linked to heart problems when used excessively. Which would have have even worse side-effects on a growing body. I also smoke and chew tobacco, do not drink, and haven t used any illegal drugs in just shy of 4 years. I m currently taking 300mg of Lamotrigine for Bi-Polar disorder. Thanks for the help.