Best tips in regard to calibrating a macbook pro screen
In my experience, with the exception of my first-gen fluorescent backlit plastic MacBook, which has never looked quite right, Apple displays ship with excellent default calibration.
Unlike TVs which are optimized to maximize their brightness in already bright fluorescent-lit showrooms, Apple tends to ship their displays calibrated for rooms with normal levels of incandescent light.
That said, if you'd like to get into color calibration, try calibrating by eye first. Turn on the advanced settings for a load of controls. Just follow the instructions carefully.
System Preferences > Displays > Color > Calibrate
If you have a good eye, aren't doing color sensitive work, and just want to get your display to "look good", this might be all you need. During the calibration, make sure the ambient (room) lighting matches what it will be while you're using the display normally.
Also, while doing the test, you might want to get some distance from the screen and squint a bit, especially for the tests that have you judging brightness levels.
If you need something more high end, you might want to look into something hardware based like these products: Pantone Huey, Colormunki, Datacolor Spyder.
Depending on which of these you get, you'll be able to not only calibrate your display so that it displays color accurately, but also generate color profiles for proofing so you can simulate what your work will look like when printed on a specific printer, paper, inks etc.
Screen calibration is usually done to a screen to match the properties of a printer, and the instructions are normally found in the printers manual.
However as you say this is hurting your eyes you could invest in a huey which matches the pantone colours.
You could also adjust the brightness before doing anything else as it could be too bright for your eyes.
Like all displays Apple's are terribly uncalibrated out of the box. Way too much blue, which is a common issue with displays for two reasons. One, 9300K (cooler, bluer white) is the standard color temperature for Japanese television broadcasts (so Japanese manufacturers, who used to dominate the display market, built a lot of displays with 9300K default white point making it a de facto out-of-the-box standard). Two, a brighter display is more noticeable on the showroom floor, simply because it's more noticeable, so consumers believe bright displays are better and manufacturers indulge this belief. Since 9300K makes colors look brighter and more saturated, even though they are less accurately reproduced, manufacturers ship displays that default to that setting so when display models are put on retailer's shelves they appear as bright as possible next to the competition. Additionally, brightness is a number that can be printed on a spec sheet, and we all know that a larger number on a spec sheet is better irrespective of anything to do with reality.
You can maybe get it kind of OK by setting the color temperature to 6500K, using some test patterns, and if you want to go a little bit further get some color filters and use those to adjust tint, etc., with the appropriate patterns, although I'm not sure if those fine grained settings are available anymore like they were on good old CRT monitors.
I would recommend just getting a calibration dongle. I have a Spyder3 Pro I got for under $100 after rebate a few years ago, and I'm really glad I did, totally great purchase. I'm a programmer, so I don't need a calibrated display for my work, but everything looks so much better and more comfortable to view. You can use it with all your computers and monitors basically forever (at least until the manufacturer drops support for some future OS), and it's pretty much a one-time thing you do after an OS install or monitor change.
As a general aside, if you are getting eyestrain you may just need to turn down the brightness. Getting it properly calibrated will help, as you'll be able to see fine detail that was previously blown out and thus won't need it cranked up so much, but unless you turn the brightness down it'll be dumping the same amount of light into your eyeballs.