Anyone a nurse? I'm freaking out. back feels sore and my sternum hurts

What could it be? All day my upper back has been feeling sore as if I slept wrong. As I was about to go to sleep my chest started hurting bad! My sternum feels as if someone is rubbing it hard and it feels like there is a bruise when I touch it. The pain is not between my boobs it's above my boobs but in the center which I believe is the upper part of the sternum. earlier I was also having sharp pain in my right side of chest below boob for a few seconds. What can it be?! I'm low key scared its a sign of a heart attack but at the same time I doubt it 😓 I'm pretty healthy and I'm 24. I was sick all week and I have been coughing a lot yesterday and today 🙊