Decreased hearing can occur generally for two reasons.
The first, as you say, is from build up of wax inside the ear canals. Q tips are actually not at all effective here, because they tend just to pack the wax tighter against the ear drum and they may also increase the risk of damaging the ear drum itself.
The second potential cause of hearing loss could be from long term exposure to loud noises, which might occur over years if you routinely use headphones at high volume.
Your primary care doctor
can help you with this problem. The first thing that they will do is look inside your ears to see if there is wax buildup. If so, they can remove it, either with an irrigating solution or with a special tool. Afterwards, they can give you a prescription to help keep the wax soft and prevent it from building back up again.
If, on the other hand, your ear canals are clean, then they may want to perform additional tests to determine why you have decreased hearing, which might include a referral to an audiologist
Call and make an appointment with your doctor at your earliest convenience, and good luck!