thank you for your query.
What you describe is definitely not normal.
Gas or indigestion
would not cause electric shock
or jolt like feeling in the chest.
Since you are a patient of MS ( cardiac disease - I assume MS means mitral stenosis
) and not multiple sclerosis, you should go in for an assessment and complete opinion by a Cardiologist.
Also consult your obstetrician regarding this issue.
IT is an unusual symptom to have in pregnancy, and needs evaluation on account of your history of heart disease