Thank you for the information,
There are some common causes of such heavy arm along with tingling sensation.The common ones are unstable angina, myocardial ischaemia, nerve irritation, electrolyte imbalance, vitamin deficiency, etc.
As per your symptoms we should first rule out the cardiac cause of such symptoms.The decreased blood supply to heart may cause such symptoms of tingling and numbness in left arm.
The other possibility could be vitamin deficiency which should also be ruled out as it may also cause such symptoms.The electrolyte imbalanvce may also cause such tingling and numbness and should be investigated.
The decreased blood supply may also be associated with such symptoms and should be treated after having the relevant investigations done.
You should have the relevant investigations done like ekg, 2d echo of heart, exercise treadmill test, serum electrolytes, serum vitamin b12 and folic acid, etc after consulting your doctor to know the associated abnormality.
The treatment depeds on the underlying cause.
Let me know if you have any doubt.