It is true that different people have different concepts of pain. What is excruciating to one person may be bearable to another, and the other way around. What is important is that pain is recognized and accepted for each person.
For example, if you go to the hospital with pain in your stomach, you will likely be asked if the pain is sharp, dull, aching, pressing, centralized, or radiating, among other descriptions. Once the type of pain is established, most doctors and nurses now use a pain scale to see how you are feeling at that moment and how you progress with treatment and time. So, you may be asked, "on a scale of 0 to 10, with 0 being 'no pain' and 10 being 'the worst ever' pain, how would you rate your pain right now?" This gives the healthcare providers a benchmark with which to work. Later, as your examination is going on, tests are done, or treatment given, you will be asked again so that your progress can be measured against your initial score.
If you are in an establishment that doesn't seem to be using a pain scale, you can still use it yourself. If asked how your pain is, you can say, "on a scale of 0 to 10...." and then be consistent with describing your pain this way from then on.