Heart Palpitations by laying down flat.

From past few days, I feel something is stuck on my throat  and I was taking antacid(digene) from the long time nearly 1 year. Now my condition is being worse, I feel something stuck on my throat and when I lay down flat for sleeping my heart beat start rising up and I woke up after walking some time, my heart beat comes to normal. I consulted to a doctor. He gave me Rabiprez-DSR and Zolent plus. Iam taking the medicines from last 10 days but results are not good. I still feel heart palpitations and that stuck feeling in throat. I had a X Ray and ecg also, both came to normal. I cannot have endoscopy due to lockdown in the city. I am very curious for knowing the reason and solution asap. Please suggest me some advice and medication. Thanks in advance.