Without more information, I can only guess at possible causes. The first question is did you have ankle pain before you started hiking again.

Anyone who starts to exercise or who increases the amount of exercise they do is likely to encounter some sort of pain. I've found that backing off for a few days and then increasing exercise more slowly eliminates almost all pains. Sometimes it can take months of remaining at a plateau.

Using trekking poles while hiking can reduce strains.

If you think the injury warrants seeing a doctor, the do so.

Soaking the foot in cold water can help ankle injuries heal. By cold, I means as cold as is comfortable, but not freezing water. Don't overdo this remedy and if the ankle feels better after soaking don't use this as a reason to resume exercise right after.

If it's the back of your ankle it could be problems with the Achilles tendon. This can be aggravated by pushing too hard up hills and taking steps without putting your heels down. Walk more slowly uphill and land with your foot flat. If you normally wear shoes with elevated heels and your hiking shoes don't have elevated heels it can also cause problems with the Achilles tendon.

Achilles tendon injuries can be serious. If the tendon snaps it's difficult to repair, so proceed with extreme caution.

You said you have almost no swelling which I interpret as there is some swelling. This is a signal that you really do need to reduce the amount of exercise.

Problems throughout the walking system, meaning your entire body, can originate with poorly fitting shoes. Shoes should have a wide and tall toe box so you can wiggle your toes in all directions. This is difficult to find in most hiking shoes. Most people select shoes that are too narrow and too short.

Buying new shoes can get expensive. I found a pair of New Balance all terrain shoes for $44.95 New Balance has wide sizes while most other brands either do not or they don't keep them in stock.

I'm going to ask you to take a $44.95 leap of faith. It could be more if you buy an expensive pair of shoes. Wear a pair of thick hiking socks when you buy shoes. Find a pair where you can wiggle your toes. Then buy a half-size bigger in length. If the store has one of those old-fashioned things for measuring shoe size, buy a half size bigger and a size or two wider. The shoe will feel loose for a couple days because it's different than you are used to.

If your feet swell when you hike, you may have to go a full size bigger.

Finally, before you do anything I just said, listen to other opinions and use your own judgment.