What I've been told is that the only way to find out if you have ADD or ADHD is to take ADD/ADHD medication and see if it works for you. Doctors can suspect you have ADD/ADHD, but it isn't like there's a foolproof test for it. Unfortunately, ADD/ADHD medication typically improves performance in people that Doctors do not suspect have ADD/ADHD as well. Chronic usage of any drug that passes the blood-brain-barrier is going to result in semi-permanent changes to your brain. Take drugs cautiously.
I can be convinced that some people have more trouble concentrating than others, but I'm unconvinced that ADD/ADHD represents anything other than one end of this spectrum. I don't think looking for a genetic cause of hyperactivity to address ADD makes any more sense than looking for a genetic cause of awkwardness to cure Aspergers.
If you're having trouble reading, that generally points to a dyslexia of some type (pretty much the definition dys=difficulty, lexia = reading).
Just imagine everything you read is being spoken in the voice of Stephen Fry. You'll have no problem with comprehension or retention ever again. True story.
ftfy
Also, speaking as someone who actually has ADD, there are better ways to treat it than with just medication. On adderall, I was more mellow but I wasn't as happy because I was too focused on everything. Not to mention the increased heart rate and decreased appetite.
In short, I was happier being able to bounce around and shift my attention.
Like with any non-severe mental disorder, cognitive therapy and self-discipline actually work well.