Hi.. Thanks for the query.. Well, the symptoms of having white coating over the tongue along with irritation and soreness is most commonly due to fungal infection known as Oral Thrush.. It is commonly caused due to intake of medication like antibiotics and steroids, dry mouth, poor immunity, diabetes etc.. You should consult an Oral Physician and get evaluated and if Thrush is confirmed as diagnosis the Physician can advise you to take antifungal medicines like Fluconazole or Itraconazole orally.. Nystatin mouthwash and clotrimazole lozenges can be advised.. Taking more of probiotics like Yoghurt and Garlic will help in faster clearing of fungus.. Drink plenty of water to prevent Dry mouth that is common in Thrush and chemotherapeutic agents intake.. Hope this information helps.. If you have further questions you can visity profile and ask me a direct questions for a detailed discussion.. Regards..