Could heart pain get better with rest?

It should: Typically, angina (heart pain) gets better when you stop to rest since the heart has less work to do and can catch up so to speak.

I hope so: One of the definitions of angina is chest pain which is 1) brought on by exertion 2) relieved by rest (or nitroglycerin) 3) of a sub-sternal nature. Most anginal chest pain does improve with rest. If it does not, it may represent unstable angina or heart attack, both of which should receive prompt medical attention.