Hi lex -
The pain in the back of your legs - is it in the thigh area, the knee or the calf?
Also, what kind of pedals do you use - are they regular platforms pedals, or are you clipped in?
Recommended by whom, and for whom?I've read that tight hamstrings mean you should lower you saddle but mine is already about half a centimetre below the recommended height.Seriously, charts are good starting points, but everyone is different. Was the recommended saddle height taken off a chart, or was it obtained from a professional fitter working on you with your bike?
My guess is either your saddle height is actually not correct (more on that below), or your cleat angles need adjusting (if you ride clipped-in)
If you ride clipped-in, if the angle of your feet on the pedals is not optimal for you, that can cause some leg pain. Some of us naturally ride with our toes pointing slightly inward or slightly outward, and the angle of the cleat on the bottom of the sole of your biking shoe should be adjusted to account for that. Some of us even turn out more with one foot than another. It can be a very subtle adjustment, but as your rides get longer you might notice some leg pain. That happened to me, and it went away very quickly when I made some very small changes to the angle of the cleats on my shoes.
Here are a couple of articles that might help (seems like I'm always spouting the gospel according to Sheldon, but he seems to be right more often than not !)
http://sheldonbrown.com/pain.html
In this article he doesn't talk about leg pain per se, but check out the section on knees.
http://sheldonbrown.com/saddles.html#height
Although, from what I've read, generally, pain in the front of the legs means your saddle might be too low, and pain in the back of your legs means the saddle might be too high. Since you say the pain is in the back of your legs (or was it the side?) then possibly your saddle might still be too high. Do you rock side-to-side when you're pedalling quickly? That's an indication that the saddle is still too high. Check Sheldon's article.
Hope this helps! - Jo.