Left arm pain aches/discomforts?

For the past week I’ve been having aches and discomforts in my upper left arm and under my left chest area. I have had these before but not I believe not as long. I want to know if anyone has any idea to what it could be? I have my cardiologist appointment Tuesday so I can see if it’s heart related or not. But most likely he will tell me no since i have had a nuclear stress test done before. But my recovery heart rate when I work out is fine, my blood pressure is good, my resting heart rate is great. when I work out nothing hurts. So I’m just seeing what else it could possibly be. Maybe a sprain or nerve damage or anything? I’m 29 so trying to figure out what’s up. Thanks you all :)