After covid and after endoscopy.

My mother ,age 55 Had got Covid in Dec Since Jan till  date having alot of acidity and burping and passing gas Stool test is normal Endoscopy is normal Thyroid is normal All tests done v recently She had also lost 10 kg in last 6-8 months due to some stress and had vertigo before Covid .she takes temsi am 40 for BP and is thalassemia minor Plz advise As currently she is getting chills at times and profuse sweating at times .. earlier since many years she used to get hot flushes due to menopause Acid reflux  is too much At these hard times,your guidance will help .plz let me know the medicine I can give her  .she doesn't have ulcers or h.pylori .reports are normal .also want something to build up her immunity Can it be something else as she is getting chills and sweating suddenly...