While there is no way to anticipate the amount of pain you will experience, arriving with certain amount of determination will almost certainly guarantee you that it won't hurt as nearly as much as you expected.
Getting a tattoo involves piercing the skin, and so there is going to be some pain involved, no matter how small the tattoo and no matter where it is on your body. The amount and type of pain experienced is highly variable depending on each individual's tolerance to and acceptance of pain.
While tattooing, the needles puncture the skin at a very fast rate and at a variable depth. The outline is usually the most painful work, because the needles are being used to create a nice solid black line that will define the tattoo, and so it is inserted deeply and carefully to ensure complete and effective coverage. The shading is usually not as painful, but this also depends upon the depth of penetration and the desired effect.
The pain you feel is generally as a slight burning or hot scratching sensation. Generally, the tattoo is more painful if applied to areas of the body where there is less muscle and fatty tissue covering bone, like wrists, ankles, chests, and other normally sensitive body areas. Upper arms are usually the least painful, while the ankles and sternum can be quite sensitive.
The tattoo pain is certainly not unbearable, here are some tips for coping with and minimizing the pain:
Find a reputable tattooist that you feel comfortable with to get the tattoo work done, the confidence you get from a tattooist can minimize your pain to the highest.
Go in with some determination and accept the fact that a few hours of discomfort without giving the tattooist a hard time will help ensure that you get a first-rate tattoo.
If you feel you can't take the pain anymore, tell your tattooist. Take a short break, or come back in a few days.
Tattoos don't have to be applied all in one sitting. Break up your session if needed.
After all, the pain you experience while getting tattooed is a unique and certainly bearable pain. Take the opportunity to enjoy a new and unique experience that will mark the emergence of a "new you" from the tattoo studio.