What Causes Light Headedness Along With Sinusitis?

Had minor bang on head 4 days ago no concussion injured shoulder and hip so been taking 30/500 co codamol till last night
I have developed a bit of a cold with blocked up sinuses some sneezing and light headed ness
Went to docs yesterday he checked my eyes said all looked fine but have since developed the symptoms I think I am lightheaded because of medication and cold but not had CT. Scan do I need one