Hi. Thanks for the query.. As per your complain sore throat along with headache and swollen lymph nodes and ulcer in mouth seems to be most probably due to viral infection only.. As viral infection resolves once the virus completes its life cycle in human body therefore you need to take supportive treatment to relieve the symptoms.. You should however consult an ENT Physician and get evaluated ad get a throat swab culture and blood test done to rule out the exact cause so that appropriate treatment can be done.. As of now you can be advised: -Anti-inflammatory painkillers like Ibuprofen can be taken to relive pain. -----Doing warm saline gargles, steam inhalation and using a humidifier in your room can be very much relieving. -You can also suck throat lozenges to soothe the throat.. -Gargle with numbing mouthwash containing Lignocaine.. -Gargle with antiseptic solution like few drops of betadine in water.. -Chew Vitamin C pellets to boost up the immunity.. -Avoid spicy and chilled foods.. Hope this information helps.. Regards.