Thank you for coming to JustAnswer with your question, and welcome.
Coccyx injuries can be very painful. Usually, the pain will be most severe when you are placing pressure on the tailbone while in a seated position. Since you are having pain when lying down and when standing, it would be advisable to see your doctor for an exam, just to make sure something else is not also injured. Whether it is bruised or broken, treatment is about the same. But if you are having this much pain, your doctor will be able to prescribe stronger pain medications.
For now, you can apply ice to the area. Use an anti-inflammatory medicine such as ibuprofen or naproxen. If for some reason you can't take an anti-inflammatory, acetaminophen (tylenol) may help. When sitting, you should avoid direct contact to your coccyx (tailbone) by sitting on pillows, a donut shaped cushion, or by leaning to one side or the other. You should also avoid constipation. Increasing fiber, drinking more liquids, eating more fruit, using stool softeners, or using a fiber supplement (like Benefiber, or Metamucil) will all help.
Here is a link for more information about Tailbone Injury.
Since you have had an xray done, it is most likely a very bad bruise, and inflammation and swelling in the area causes the pain.
Try applying an ice pack for 15 to 20 minutes several times during the day. You can alternate acetaminophen between doses of naproxen for more pain relief. Be careful not to take too much of either drug if you do this, so write down your doses.
You might want to give your doctor a call to report the increase in pain and swelling. You might need a stronger pain medication for a short time.