Hi. lower part of neck , behind ear on right side , it's been aching off & on as i burp . have acid reflux , stress & anxiety. had sinus issue. idea?

Post ear ache: May be mastoiditis which is like sinusitis ( it s in the bone behind the ear). May need antibiotics and also treatment of GERD/ reflux. Would also check if you have GERD for H pylori a bacteria that can complicated GERD. H pylori can be diagnosed by blood test or breath test . Consder GI/ ENT follow up . Would also ask about TMJ .Avoid GERd triggers , alcohol smoking, spicy/fatty foods, caffein