Hello Thanks for writing to H.C.M. I have gone through your clinical history regarding headache and suspected sinusitis. As you said about two possible conditions which causes and exagerate your headache, these are head washing with water and in days close to showers. These aggravating factors are not in favor of sinusitis they are actually favoring migraine. To find out the cause of headache you are advice for these investigations- (1) C.T. scan of paranasal sinuses and head. (2) Blood pressure recording. (3) Ophthalmic exmination for Acuity of vision & to rule out sqint. (4) Blood sugar- F & P.P., Lipid profile. Thorough examination of C.N.S., C.V.S and ENT along with the help of above investigations one can reach to a diagnisis which may accordingly be manage. With Regards.