Here are a few tips that were passed on to me:
Begin equalizing on your way to the dive site.
Take Sudafed 2-3 hrs prior to diving. There is some controversy with PADI about this so I'd check with your MD on this first. Mine OK'd it.
Try and descend in a head up, feet down orientation on a descent line. Take your time, equalize often. Every few feet. If you start to feel pain or excessive pressure you've waited too long - go back up a few feet and try again.
An Instructor said another option is to 'exercise' the Eustachian tubes by blowing up new and 'tight' balloons when not diving. He claims its helps although I cannot verify this myself.
This is direct from Rodale's online scuba medical section. Your not experiencing sinus barotrauma's from what you said, but you MAY be in your inner ear(s). Per Rodale's Scuba Magazine Online:
Symptoms of Barotrauma
"The most common barotrauma symptom a diver experiences may be mild discomfort to intense pain in the sinus or middle ear - this is usually the first indication of a problem in equalizing. Middle ear barotrauma may also include symptoms of ringing or hearing loss. As blood or fluid accumulates in the middle ear a diver may experience a partial, complete or muffled hearing loss as well as damage to the inner ear. Roaring in the ear, nausea, vomiting, dizziness, a sensation of spinning and decreased hearing may also indicate inner ear barotrauma, which requires urgent specialized treatment. *Blood from the nose or in the sputum is also an indication of barotrauma and does not have to be associated with other symptoms. These are symptoms that should probably end the day's - and possibly the week's - diving. Continuing to dive with barotrauma may result in serious injury."
If it continues I'd recruit the help of an ENT, preferably one with diving medical experience. Could be some physical condition that MAY need surgery to correct such as polyps, etc. although many times its just fluid in the ears, allergies, congestion or closed or narrowed Eustachian tubes and/or poor equalization technique.
Good luck...