I had inguinal hernias on both the left and right sides, and had them both repaired at the same time about eight years ago. From the pain standpoint, the first twelve hours afterward were the worst. It felt a little like having the flu and being kicked in the balls at the same time. But it got much better very quickly. Things which will cause discomfort include coughing, sneezing. laughing, and trying to sit up if you're lying down. It's better to sleep in a semi-upright position for the first few days. I had a local anesthetic. Supposedly, there is more pain if you have general anesthesia. Apparently, the local anesthetic has some residual pain killing effect that lasts for awhile after surgery. Some of the prescription pain killers given to people who have hernia surgery have the effect of keeping the intestines from going through their normal muscular contractions, and for that reason they can cause severe constipation. I had that experience and had to resort to drinking prune juice. I felt like I was shitting bricks. What I remember most about the entire experience wasn't the pain, but the general feeling of fatigue. It was several months before my energy level returned to normal. Also, there was a lot of genital swelling, similar to what you would get from vacuum pumping. Most of that went away after about two weeks, but it took about three months before it was completely gone.
Hernia repair is about the most common type of minor surgery, and it's just about always successful, with no significant complications. However, it definitely isn't fun.