If you are talking about inguinal hernias in the groin area there really are no symptoms. I had my first when I was 28 and five more since I was 49. I am now 60. With the first there was a dull pain which sent me to the doctor for the turn your head and cough test. The next two follow surgery, which is not unusual. Three were found through routine physicals at different time--the last time was a double with one on each side. When I had my first one repaired, I was in the hospital for a week. Now it is same day or overnight surgery and you are sent home. Looking at limited duty for about six weeks. The other three were found the same way. If left untreated, they can strangulate causing a kink in the intestines and severe pain. Go straight to the emergency room. It is not going to go away.
Hiatal hernias may result in difficulty swallowing or acid reflux. They can usually be treated with medication. I have one of those. If surgery is needed be aware a regular surgeon will do the procedure from the chest. A thoracic surgeon may go through the back, which takes longer to heal. My mother had to have surgery and it was done that way and she was in a lot of pain for a long time. Do not trust me, get other professional opinions if you have a hiatal hernia and surgery is proposed.