do you and your son's father share legal custody of your son? If so, who has final say? If he does, then there's not much you can do. If he has sole legal custody, there's not much you can do.
My brother has ADD and I worked for several years as a child case manager and I can tell you that it's not uncommon for kids to NOT outgrow their ADD/ADHD, depending on the severity. Don't you know adults who fidget, won't sit still, start things but never finish, jump from job to job due to boredom/lack of challenge, change hobbies yearly, etc, etc, etc. That's Adult ADD. It's alive and well.
While it's true that he may outgrow it, are you willing to suffer the consequences until then? Most kids who are properly treated for their ADD/ADHD (in whatever form that may take) do much better in school. Their social skills are better and they learn how to form relationships better. So, if you are waiting for him to outgrow it, you may be setting your son up to not reach his full potential in school (which could affect his ability to get into college and/or get a scholarship), and setting him up for a frustrating social life.
Medication can be a great thing or bad thing for kids with ADHD. There are different types and each have their own level of effectiveness on each individual child. There are also more unconventional treatments of ADD/ADHD. However, if your son lives with his dad, then it's really his decision on how he wants to handle the situation. Hopefully your son is being carefully monitored by a doctor. Those meds can sometimes take time to even out and get the doseage right. Your son should feel comfortable talking to his doctor about what he's feeling so the doctor can adjust if necessary.
Hopefully you guys can work together on this, but medication really is a good solution for most kids who are truly ADHD/ADD.