Hello dear, thanks for your question on HCM.
I can understand your situation and problem.
Chest pain on coughing and sneezing is characteristic feature of pleurisy ( inflammation of pleura ).
Pleurisy can be seen in pneumonia,
tuberculosis,
pleural effusion etc.
So get done chest x ray to rule out all these causes.
If chest x ray is normal, then no need to worry much.
Stress and anxiety can be the cause for your symptoms.
Stress can worsen reflux disease.
So control of anxiety is needed in your case.
Consult psychiatrist and get done
counselling sessions. Try to identify stressor in your life and start working on its solution.
You may require anxiolytic drugs too.
Don't worry, you will be alright.