Every person is different and so are their reactions. You can build resistance by getting stung over time, but it can also go the other way and sensitize you to it. Localized swelling is normal, but a systemic reaction would indicate a more serious situation. When I first started keeping bees, I had enormous disfiguring swelling. But I was advised to start a regimine of daily stings, and it worked. In retrospect, it probably wasn't the best advice, but still today, a sting is more a momentary annoyance unless it's under a fingernail, or on the nose. I don't think 10 stings a year is many at all, and I have had many more than that hiving the odd angry swarm, or digging through a hot hive looking for a lady to behead.
Something to keep in mind. If you are on various medications, the sting may be intensified dramatically. Even aspirin can have an impact.
You must be getting ready to go after that hive in the wall of the pump house huh?