I would get the hub serviced. If you are a regular rider and complaining it is your only transportation not taking care of it is not an option. You may need to leave it at a shop and let them tune up the bike and replace oil at the very least.
Yes it could just be misaligned and need adjustment but 2 years of known heavy riding and another 2 years of potentially unknown riding which could have been worse or better not that it matters would require some servicing.

If you only ride a bike and cannot fathom getting around without it you need a second bike so you can drop off your bikes for service and leave them and get them properly serviced regularly. Problems don't get better they just get worse and worse until they get really expensive and the bike is quite dangerous to ride. I know it is tough to think about but either you need to leave the bike and have a backup bike or you need to have other ways to get around.

Keep your bike in good condition and take really good care of it and it will last a long time and serve you well.