All morning I have gotten a severe sharp pain over my heart with tightness. Comes and goes. Possible reasons? Should I call my doc? 28yr f, 25wks pregnant

Chest pain & pregnan. Any "severe" pain occurring over the chest and lasting a few hours "all morning" should be evaluated. The fact that it is "sharp" does suggest that it may be musculoskeleetal type of pain, which is much less worrison. Acid reflux, which is markedly increased during pregnancy is possible. (try an antacid. It can't hurt.) a rare but more serious problem could be a blood clot to lung in pregnancy.