Welcome at JA.
It looks from your details the you are suffering from olfactory hallucinations.
Such type of hallucinations are encountered in-
-Head injury-Nasal disorders-Brain lesions like tumors-Partial status epilepticus
If you are suffering from this since last long time then you should consult to your neurologist & should get evaluated by having MRI SCAN OF THE BRAIN .
Hope this will help you.