Hi.

I understand your concern .

You have persistent feeling Of being ill suggest anxiety and hypochondrial tenancies.

Detail psychological evaluation will give more confirm diagnosis.

Feeling like heart attack also suggestive of panic attacks which has similar features.

But investigation come normal in such attack.

Need to relax and accept this fact that psychological reasons behind your physical symptoms.

Anxiolytic medicine like etizolam and clonazepam will help.

Meditations and exercise like deep breathing can be useful.

Proper sleep and diet can help .

Consult psychiatrist for further evaluation and treatment .

I hope I have answered your question .

Thank you .