Here is more info on dermatofibromas:

Dermatofibroma | DermNet New Zealand

Notice these are most commonly pigmented, and painless.

How many of these do you have? How old are you? Have you had a uric acid test?

Here is another site...another possibility:
Calcinosis - HealthCentral Encyclopedia

This can happen if there is an injury or repeated stress on a soft tissue area. The shins have nerves and tendons close to the surface. If you get shin splints often or have injured your lower leg recently, calcium can deposit there. These can be painful as the calcium crystals are sharp and irritate the surrounding tissue.

These often resolve on their own. You might try soaking in epsom salts, which can improve circulation to that area, and improve blood flow to dissolve them away. These are typically not pigmented and are actually below the skin.

There is an over the counter lotion that has lidocaine in it which works well on localized pain areas. It is called Aspercreme Lidocaine. Apply this lightly (heavy application is not necessary) and see if this helps with your temporary pain.

People with high uric acid levels sometimes get small lumps under the skin composed of uric acid buildup. These are called uric acid trophi. A simple blood test can show if you have elevated uric acid levels, and prone to gout.

Questions and Answers About Gout

You need to see a DOCTOR and not a physician's assistant.