Feeling stressed and pain in chest.

I had history of depression. I took medicine for same for 1.5 years. I'm again feeling stressed for like 3 months. I overthink a lot. I keep thinking about bad things that happened with me in past at night. I feel tired all day. There is a feeling of indigestion all day. It's like food is stuck in my throat. I had 2 panic/anxiety attacks within 15 days. I thought that it was related to heart. So I had my ECG done, it was normal. Still I am having pain in my chest for over a month now. Sometimes it radiates to my neck and left arm. I'm also having pain in my back. Sometimes there is a feeling like my nerve is stretching in my upper left arm. Sometimes it feels like I will die of heart disease. When I am about to sleep, sometimes my body gets sudden shock and sortness of breath. I sweat even if AC is running and temperature is cool. I get shocked when there is a sudden sound which I was not expecting. And sometimes my resting heart rate goes over 100 especially when I'm in a hot area.