What could cause swollen glands on neck (back and front). slight sore throat and headache not too bad but no other symptoms?

Get checked.: Allergies can present like this sometimes. Try benadryl (diphenhydramine) and see if it helps. if not, it's likely a viral or bacterial infection. Strep can present with minor symptoms, especially in adults, so it is important to get checked for this, especially if you have been exposed to strep or if kids around you have sore throats, and fever.