If you have a health history of heart issues, disorders of the thyroid gland can worsen old cardiac symptoms or cause new ones, and can accelerate the underlying heart problem. Regardless whether your symptoms are thyroid or a heart issue related it seems you should be evaluated by a doctor.
For instance, if thyroid related, that will effect normal cardiovascular function. If the function of the heart the condition can reduce contactility and/or reduce the heart's ability to relax is reduced and less blood is pumped into circulation. Either pumping or relaxing , phase irregulatity can cause your symptoms as cardiac output is/may not be sufficient to meet system's demand for oxygenated blood and as a consequence SOB develops.
Also, there could be an arrythmetic disorder. Could be your system's reaction to the energy drinks.
Thankds for your question and if you have any other comments or questions you are welcome to respond. Take care,
Ken