At 3 years old, I'd just chalk this up to his exploration of a new world opened to him and that it is perfectly normal. My 14yo was this way and she is an exceptional student who has been in the AIG program since kindergarten (academically & intellectually gifted). She earned all kinds of awards throughout her school years including the Student of Excellence Award from our governor! Last year in 7th grade she was nominated and inducted into the Junior Honors Society. Her classes are all advanced classes and she is on the university track because of her academics.
The one thing your child can benefit from right now is educational toys and your time. Your child is reaching the end of a time in his life where he will have learned more in a few short years than he will learn ever again in such a short time span the rest of his life. Take advantage of it. Teach him to read, his colors, shapes, letters, numbers, simple math, cooking for kids, and continue to teach him more challenging things to hold his attention. It will pay off in the end.
With regards to ADD/ADHD, I am not a big fan of medicating these children forever. Our oldest child has ADD. She also has a heart condition, which was always in conflict between the medications for her heart and the short-term medication to control the ADD until she mastered the behavioral modifications that allowed her to come off the medication completely and allow her to function as a normal child and adult without the need for yet another pill all because she was a bit high-strung.
We found the best psychologist in the field to test and treat her as well as teach her the behavior modifications because we did not want her on medication for the rest of her life. The best thing about this psychologist and what made him a great person for this job for both parents and the child, is that he suffered from ADD/ADHD as well and did not take medication to control his condition. He used behavioral modifications, the same ones he taught his patients no matter their age. It was a blessing. Within about 3-4 years, our oldest was completely off the ADD medication and had all the behavior modifications learned and implemented to the degree that it was as natural as walking and breathing at the same time. It serves her well both psychologically and medically, especially with regards to her heart condition.
Right now, your son is entirely too young to even begin thinking ADD/ADHD. He's a boy. Child-proof the house and find educational toys that will push his imagination to the farthest recesses of his mind, prepare and set a schedule for one-on-one time be it with a single-parent household and the child or a household where both parents are there for the child and give him that both parents with child activity time. Throw in educational ideas as well. You might as well use this time for the best benefit for your child now while he will learn and retain the information due to his age and the way his mind works.
It would also be beneficial to set up play dates for him with children his age. This will give him socialization skills he will need when entering school. Think of how you can turn something playful into a lesson and use that for his benefit in the here and now. This is why our youngest child is nearly 2 full grade levels ahead of her classmates and taking advanced classes to prevent her from becoming bored and the possibility of giving up if she were placed in regular classes vs the advanced ones.
Give it time and considering the activities you bring into your child's life and how it will benefit him at a later date.