Extreme Insomnia and Thumping Heart Beat

I started to suffer from a thumping heart beat at night about one month ago. The thumping is usually in the left side of the chest but also sometimes in the right side. This has caused terrible insomnia and I only sleep on average four hours per night (and only after laying in bed for several hours awake). During the night I can hear my heart pounding and my upper stomach and lower chest area is also 'growling'. It's worse when i lay on my side. If I sit up or stand it's fine.

In the past week I have also started to suffer from intermittent chest pain, mainly on the left of my chest but sometimes also on the right. I have had many heart tests (echocadiagram, stress tests, etc) which are all normal. Cardiologist says there is nothing wrong with my heart and it must be psychological.

I gave up smoking just as the heart symptoms started (after 27 years). However to be fair, I was suffering from insomnia prior to this for many years, although not as bad. Daytime exercise seems to make the heart pounding worse.

Can anyone recommend a treatment?