I've been having fatigue, left arm pain and foggy brain to the point where i have a hard time putting a sentence together. can this be some sort of heart problem?

Yes, but...: If you're 24, it's very unlikely for this to be a heart attack or stroke. If you were 60, and this just started 10 minutes ago, i'd be very worried and would recommend the er immediately via ambulance (911). If you are 24 years old and this has been going on for a few days, schedule an appointment with your doctor to get checked out.

Unlikely: Given your age but further evaluation warranted given you symptoms.