I am having lower abdnominal pain near my hip, it hurts to touch it, stretch, cough, sneeze, make sudden movements. I'm also starting to feel nauseous. What is causing this, and should I go see a doctor?

A few weeks ago I started having heartburn bad with no help from over the coounter medicines,the heatburn is still going on but now my bowels have turned black very black. could this be linked together or what...