Inguinal hernia. More common than you’d think.
Four years ago, I had an inguinal hernia on my right side (same thing as you - doc pointed it out), which I had repaired at the time. This past fall, I popped the left tire and had it repaired over the winter.
So how do you know if you have one and what does it feel like? It depends. I can only tell you what I went through. The right hand side one I actually had for a couple years and didn’t know it. I never felt anything - but I did notice some asymmetrical-ness of the lower right side of my abs compared to the lower left side. However, at that time I was doing nothing to strain said hernia (exercise, lifting, etc) as I was just working at a desk - so I suspect that had a LOT to do with why I never knew about it. That, and not having gone to the doctor for a checkup in years.
Knowing that once someone has one on one side (since its usually genetic) that it pops on the other, I had my senses peeled for the other side to go for the next few years. I suspected I was developing one, but the doc couldn’t detect it. I distinctly remember one day when jogging last fall when I felt something near my hip, and knew that it was starting to get worse. It didn’t hurt - just felt like a pinch. That happened a couple more times over the next few weeks before I went back to the doc, and it was confirmed (although even then, he had to try multiple times to feel it). I ended up getting a truss and wearing that when I went jogging, with no problems. Over the winter I got it repaired, after my half marathon was done in October, and when I had ‘use it or lose it’ vacation time from work to burn through.
So, what I’d say about your situation (and obviously IANAD): keep an eye on it, be aware for anything feeling kinda out of the ordinary near your lower ab area, and go to the doctor every so often to see if it has fully developed. Once it has, get it surgically repaired. There are multiple ways to do that - many places are touting laproscopic as the next best thing, but both of mine were open surgery tension free mesh repairs. I think different doctors have different preferences, and when I asked my doctor about laproscopic on the 2nd one, she said that there is a slightly higher rate of reoccurance with lapro. Anyway - whichever option you go with, you want to get it done earlier so that the defect is smaller and recovery time is quicker.
Speaking of recovery time - they may say you can return to work the next day, but give yourself 3-4 days of nothing but lying around. I found, especially with the first one since it was a much larger defect, that if I was standing up for too long (even just long enough to get to the bathroom to go pee), it would start to hurt a bit. Lying down flat was perfectly comfortable. After a few days, you start being a little bit more mobile. After about a week, you’re generally able to get around to do lifes everyday tasks. After about a month, you’re largely good to go. I think it was about 4-5 weeks after my second repair that I was able to start jogging again (short distances - less than 2 miles) with no problems. Actually, the second surgery was great - I had a great excuse to stay home and not go to work, I got to play Civ IV all day, and had a great excuse to have someone else do all the work around the house 
EDIT: ironically, the first hernia REALLY started acting up once I had the surgery date set. Anytime I laughed hard or did any lifting, I could feel something not quite right… kinda squishy. That was the only indication I had for that one. But for the second one? Only those couple times when I was jogging, where the bouncing exacerbated the already weak abdominal wall.