Hello,
Some of the coating with a yellow tint can be attributed to your smoking. You most likely have a strep infection, viral component, flu or other respiratory infection starting to develop. Step infection can be diagnosed with a simple swab and lab test. I suggest taking Antiinflammatory medication such as Tylenol or Advil. Monitor for a fever, rest recommended and keep hydrated. Schedule a visit to with your physician to confirm a diagnosis or if your condition feels worse. Appropriate antibiotic or other prescription medication can then be prescribed by your doctor.
If pain becomes localized to a tooth or swelling occurs in the jaw, you can see your dentist for an x-ray and additional diagnosis. An oral yeast infection can have a burning tongue with a coating. This condition may require Antifungal medication such as Nystatin. You would require an evaluation for a dental infection, diagnosis and prescription medication. Ulcerated areas are often viral in nature and will heal in one to two weeks. Avoid irritants, rinse with warm salt water or apply an anesthetic gel for relief of symptoms while area heals.
Thank you for your inquiry. I hope you find some relief soon. Please follow my suggestions especially if your condition worsens.