What to do when you experience pain when walking and sitting at the end of the spinal cord, right above the butt as I fell & hurt it during iceskatin?

Exam - bone scan. May simply have fractured your tailbone. Have your physician check for sacral fracture. If in doubt, obtain a bone scan which will confirm the diagnosis. Unfortunately, if this is a sacral fracture, it may take a while to heal. May qualify for a sacroplasty depending on the findings.
Lumbar spine xray. You could of fractured your coccyx. Treatment is usually conservative - getting a donut pillow to sit on can take the pressure off the painful area. If it's not contraindicated, anti-inflammatories like Ibuprofen can help as well.