How do I get rid of bad heel pain?

Many ways. As long as there has not been trauma to the heel you can try ice, stretching, alleve (as long as no allergy), over the counter heel supports.
Depends on the cause. Heel pain is most often caused by plantar fasciitis, a condition that is sometimes also called heel spur syndrome when a spur is present. Heel pain may also be due to other causes, such as infection, tendonitis, arthritis, stress fracture, nerve irritation, retained foreign body, bone tumor, or a cyst. Have it evaluated by a professional and get the appropriate treatment.