Hello, i have had heartburn for 4 days straight. it usually start few hours after waking up and leaves in the afternoon. this cycle has gone for 4 day now?

Gastroesophageal reflux is the most common cause of this. Raising the head of your bed 6 inches and avoiding certain foods that may exacerbate this, such as acidic or fatty foods may be helpful. If not helped, try over the counter medicines, such as famotidine, and lastly one of the proton pump inhibitors- but use the minimal amount of time. If have bleeding or not helped, check with doctor.

I assume you're not eating a huge breakfast as large meals can provoke more heartburn. In addition to Dr. S's good advice, avoid caffeine, alcohol,aspirin and anti-inflammatory medication like ibuprofen or naproxen.