It's important to keep a written record of your pain and suffering. These are called your "general damages" or "non-economic damages." Your journal should contain short statements about what hurts and how it has affected your life. For instance, an entry might read: "6/1/12 - muscle spasms and pain in neck - woke up several times last night due to pain. Couldn't go to Six Flags with kids as scheduled."
This is very helpful evidence that we can use to establish your pain and suffering. "Pain and suffering" is the cash compensation you receive above and beyond your economic damages (e.g., medical bills and lost income). Other types of damages that you should record are inconveniences, anxiety, emotional distress and ways in which you've been unable to enjoy life as you normally did before your injury.
Tell your doctor how your injuries and pain have affected your life. For example, when the doctor asks how you're doing, you could say, "Well, doctor, not too well. My neck still hurts and the pain wakes me up several times at night and it's caused me to miss several events with kids."
Keep your journal with you, so you can write things down as they happen. A spiral-bound notebook is sufficient, which you can buy at any grocery or drug store.
Taking the time to write down your pain and suffering is part of your "job" to properly document your personal injury case for the insurance company. Remember, though, whatever you write can be "discovered" by the insurance attorney in a lawsuit, so be careful what you say in your journal.