Yes, yellow coating on tongue and bitter taste in mouth are consequences of having acid reflux. Bitter or sour taste inside the mouth occur as soon as the contents inside the stomach (stomach acid and occasionally, bile), reflux up inside the esophagus, usually, reaching the back of the throat, leaving a sour or bitter taste inside the mouth.
I have given you more detailed answers for the same questions you asked on the other topic "burning down spine and shoulder blades" from February.
You can check my last post on that topic to read the answers.

Do you take some treatment for your condition?
For how long you are bothered with acid reflux?

If you want, we can continue our posting on the old topic.

Waiting for your post!
Marija

im waiting to have endoscopy done on 23rd may to see what is causing my stomach and upper back to hurt.i had helicobacter pylori last year but had breathe test and it had cleared up.im just wondering if i could have ulcer now and it could all be combined with acid.i cant take any medication until after endoscopy .im just taking odd paracetomol at moment.

would acid show on an endoscopy?

Helicobacter Pilory is a bacteria that's directly associated with gastroduodenal pathologies like chronic gastritis (inflammation of stomach lining), duodenal (first part of intestine that is attached to stomach) and gastric ulcers.
Doctor will examine the inside of your esophagus, stomach, and duodenum (the first part of the small intestine), check the walls and tissue of the upper digestive tract for some lesions (changed type of lining, narrowing, ulcers).

Have you been treated with antibiotics for Helicobacter pylori?
Did the acid reflux start after that or you had it even before you were diagnosed with this bacteria?

i have been treated with antiobotics for helicobacter pylori in october. all this with tongue and stomach srarted in december . would they tell me on the day if they was something like ulcers?

I asked you if the symptoms of GERD started after you were treated for the bacterium, because Helicobacter pylori is associated with a lower severity of symptoms of GERD, as well as a lower incidence of Barrett's esophagus. Some studies have shown that patients who are treated for Helicobacter pylori can develop symptoms of GERD after the bacteria has been killed. If you have Helicobacter pylori and GERD, both disorders must be treated.

Endoscopy provides a sensitive, specific, and safe method for diagnosing peptic ulcers, allowing direct inspection and biopsy (the physician can see abnormalities, like inflammation or bleeding, through the endoscope that don't show up well on x rays. Also, can insert instruments into the scope to treat bleeding abnormalities or remove samples of tissue (biopsy) for further tests).

The results of the endoscopy with the symptoms you have will give your physician enough material for the final diagnosis.

Do you feel pain below your breastbone 2 or 3 hours after eating?
Do you get stomach pain that awake you during the night?