The condition that you are experiencing may be caused by an infection, and the yellow discharge is a substance called pus. The problem is medically called otitis externa. This is a problem that is also more commonly known as swimmer’s ear. This problem is not exclusive to people who spend long periods of time underwater and can actually affect anyone. This is a best guess, as the problem could also be behind your eardrum in the middle ear, and if this is the case then you need to see a doctor mmediately. However, infections of the middle and inner ear would have been much more painful and the discharge coming out of your ear canal would be unlikely. The treatment for this condition is to take antibiotics and stop the infection and this can be done using home remedies. But in order to avoid permanent damage to your ears, you must visit a doctor and take some powerful antibiotics as well.
Swimmer’s ear is a problem that is caused by torsion injury to the delicate skin of the outer ear or ear canal. What happens here is that you end up either being in contact with chemicals that irritate the skin in your ear, or that you swim in polluted waters. In case you are not a swimmer, otitis externa can still affect to you. Typically, torsion injury that causes this kind of an injury occurs due to some kind of jerking action from pulling the cartilaginous outer ear to the point that you rip in the skin in the canal. Cleaning your ears with a sharp instrument also causes a tear in the skin that could lead to this condition. This is the reason why you should never put anything in your ear to clean it and allow the ear to push out wax on its own. Wax is secreted far back in the ear and pushes out older batches of wax until it is close enough to the outer ear to fall off or to be washed away.
Treating your condition would require some antibiotics like amoxicillin, which is what your doctor would probably prescribe to you. Your doctor might also clean out your ear with some hydrogen peroxide. This is something that you could also do yourself to save some time. Take a few drops of hydrogen peroxide in a pipette and drop them into your ear. This will clean out the pus and infection. Next, drain the ear completely and wait for it to dry out before pouring some diluted tea tree oil into it. This will serve as an additional disinfectant. Place some cotton wool in your ears to seal it. Repeat this procedure until you completely recover.