get some salt in warm water also an aspirin which dissolve in water easily and do groggles with it . and check if your nose is running completely like white water or its getting blocked, u r feeling lethagric.. you think it is flu or common cold. to some symptoms it can be. check out may be you have pollen allergy its spring season so you may be allergy. 

take 1 pill every night of cetrizine hydrochloride maybe you feel better, drinking vitamin C hope it can help you out.

I am a J.D., not an M.D. but my guess would be that in the daytime we are too "distracted" with work, and "stuff" whereas at night, we are relaxed inbed and it is THEN that we notice the sore threat more.

What I do is gargle with warm salt water before going to bed. I find that it helps a bit.

Best of luck!