I've been having stomach pains since this afternoon and i have a bad taste in my mouth what should i do?

You can: Try over the counter medications, such as prilosec. If this doesn't help, you should see your doctor because it could be appendicitis, especially if your right lower abdomen starts to hurt.

Consult your MD: Bad taste in your mouth and stomach pains, may be from gastro esophageal reflux or gastititis you can try over the counter acid suppression therapy like omeprazaloe or ranitidine but if no relief consult your doctor.