As a parent of a 5 year old boy and a teacher, do not be bullied into medication without seeing a neurologist. Teachers, other parents, and most of all a general pediatrician, can not determine any type of attention deficit order without specific testing. Your son's behavior is a red flag, but it is not a diagnosis. The only reason I say that is because his behavior has required some type of response, by the adults in his life, in different settings.
Before, you jump into that lion's den, you can check his sleep schedule, he needs around 10-11 hours. Early bedtimes vs. later bedtimes are also seen to improve energic behavior.
I would start with a diet change. I am not a health food nut, but I am a believer in healthy choices for children. More fiber, less processed sugar and flour. Studies have shown, that most people react to red dye, white sugar, and flour. Although my family still has that in our diet, it takes a backseat to fresh fruits, 100% juice, lots of water, and whole grains. Breakfast and snacks especially need to be watched. What is nice is you can find healthy alternatives in your regular stores now.
Studies have also shown that children with a lot of energy should be active in some type of physical activity several times a week. It gives the body the excercise it needs. A park can also do the trick, so does running and moving for at least 30 minutes.
I am not kidding. It can be that easy to turn around if it isn't ADD or ADHD. Watching him will not give him the ability to turn it around, making some changes will. If it doesn't change for the better, then you can have him tested by a specialist. The next changes may be medication, but that should not be the first thing you try.
My son still has a lot of energy, but I have really worked on building his attention span by reading books, doing puzzles, working on coloring and painting, and other sitting activities. This quiet working time has helped tremendously. We also chose 1/2 day school for his Kindergarten. This allows him to have a great day all the time, because it is the best of both worlds. Next year, he will be developmentally ready for all day.