Thanks for posting on HCM,
Per description it will be wise to go to an emergency room first.
It is very possible that given the location of the pain, the problem might be coming from your heart and you might be having an unstable angina pectoris
or coronary artery diseases (a cardiologist will need to be consult soon enough). Other possible causes of pain of the upper left side might be costochondritis
, acute pancreatitis
etc etc. You will need that an internist consult you besides your gynobs as your problem is not necessarily related to pregnancy (and even if pregnancy related, might still require management expertise of an internist). EKG, blood tests, cardiac ultrasound, chest x-ray will need to be done in order to determine cause.
Hope this helps