Heart or GERD

please help!!!

i was diagnosed with gerd and erosive gastritis almost 2 years ago. was free of meds since about 1 year. anyhow it seems it has come back with a vengeance!!! my esophagus hurts i wake up with mouth full of strange saliva i always have phlegm in my throat and I am on Protonix 1 x day !!!

i sleep with elevated bed, i eat 2 meals a day and very light at that and wait 3 hrs before i go to bed. anyhow my question is this lately that my gerd is worse when i do my treadmill in the morning i get pains like you've scratched me in the back and in the front . naturally i am worried it could be my heart but when it happens my heart rate is fine i don't feel lightheaded i feel fine and it goes away even if i don't stop my exercise. this kind of pain sometimes comes without exercise too but i am buffled why . i try to exercise without even having had my pills(thyroxine, zurcazol) . the pain is not severe but i would like some reassurance . any thoughts/advice. i am 36fem hashimoto thyroiditis/had my annual heart check up last month - doc said i can exercise as usual she did an ekg and an echocardiogram, she saw some mild regurgitation but she said it's insignificant and i shouldn't use it as an excuse not to exercise . my resting heart is in the 50's when wake up in the morning and when i go to bed at night.
do you think i need a stress test ? i had one done about 5 years ago.