I have a pinching feeling that happens in my left side of my chest, comes out of nowhere then fades. 23 year old male. could it be a heart attack?

Unlikely: Sharp or pinching discomfort is almost always from the thoracic cage and not from cardiac issues, this is especially true in people under 30 years of age.

Very unlikely: In you age - it would be very unlikely. Pain is also not typical. Women most commonly present with shortness of breath. If there is a pain it is more pressure - like or squeezing, location is also retrosternal ( breast bone ).