In a diabetic having heart attack, there is chest pain, but this pain is different in nature than in a non-diabetic. This pain is often mistaken for other conditions such as indigestion. this is because of diabetic neuropathy, damaging the nerves controlling the heart and also the chest and back muscles. This can cause delay in seeking help and this can be dangerous.
Also diabetics are twice or thrice as likely to have a heart attack, as a non-diabetic. Thus the danger is further increased.
So PLEASE be careful, take immediate steps if there is any discomfort. It may literally save your life.