For the past few days, the left side of my chest (specifically right above my breast and the forearm/shoulder area) have been achy/sore; not an unbearable pain, but a subtle dull/uncomfortable feeling. I've also been feeling like I've been having to take harsher breaths in order to get oxygen; though I work out every day and doing simple tasks + working out doesn't make me winded at all. Since yesterday I've also been experiencing other things, such as dizziness, cold sweats, and nausea. I also just started to feel stiffness/pain in the left side of my neck, but I think I might've pulled/strained a muscle from lifting something a few days prior. All of these things seem to be symptoms of heart attack, but I'm 22 years old, I don't have a family history of heart attacks or heart diseases, I work out at least 4-5+ times a week for an hour, and have an average diet (some days healthier than others, some days not so much). Could this be something common/non-threatening, or should I be concerned?