Occasional pain in chest and left arm.

A few days back I had palpitations at night before sleeping, so I consulted a doctor and took ECG and ECHO tests, both were normal, and Doc told me I'm just being anxious, but I couldn't handle it mainly because I had muscle spasms in both sides of my chest. I also took TMT which turned out to be normal. But a few days later now I'm getting these flashes of slight pain in the left arm and back. The left arm gets cold sometimes which triggers panic, I just wanna know if everything is normal with my heart, because I feel this is the main cause of my triggers, I spiral down into panic whenever something happens in my chest or left arm. These pains I'm experiencing aren't long lasting, this just happens randomly out of the blue for a few seconds.