What Causes Recurring Crushing Pain In The Heart?

Hello everyone! So, I am actually terrified to go to a doctor.. so I thought I d post here first, and see if it is actually anything. Over the course of last year to now, I have been getting this feeling in my chest. The best way to describe it is my ribs are crushing my heart, after this I swear I can feel between 3-5, heart beats and they are extremely painful. This feeling is not constant, it usually occurs once a month after sitting for an hour. However recently, it has been more around three times a month. I am an active person, and I workout. any thoughts on what it may/may not be? Thank you!