My feet pain after i run 18k how can i treat this pain?

See below: You want to try to protect the foot before having the pain. A custom orthotic will help to control the foot motion and decrease strain and hopefully pain. For the pain, i would take some aleve (naproxen) and use ice to the foot.

Rest: 1. Run 17k 2. Wear proper shoes, replace shoes if necessary 3. Over the counter high quality orthotic inserts may help. 4. Stretch appropriately before and after running. 5. See a foot and ankle or sports orthopaedist to evaluate for stres fracture or other problem.

When you run.....: Make sure you wear good socks and have good insoles in your shoes. Use thorlo for your socks (www.Thorlo.Com) and spenco (www.Spenco.Com) for your insoles. I would use the running socks and cross-trainer insoles.