Thanks for providing that additional information. Not being there, its impossible to say what this is, but from what you write I can potentially narrow this down a bit.
Because this pain does not worsen with food and seems unrelated to food it is likely NOT caused by your gallbladder, liver, or pancreas.
It is also not likely to be appendix related either.
It hurts more when you cough. Coughing changes the pressure within your abdomen, and does use some muscle groups. Its possible that you have muscle strain from something you were doing. Its hard to tell if the ball like thing you are pressing on is your xyphoid process, at the bottom of your sternum. That indeed makes misery when its pressed upon.
However likely that may be, and no way to tell without an exam, its not very safe to leave it that way...especially when there is a possibility that this could be a rather dangerous situation called an aortic aneurism...meaning a large blood vessel in your stomach has a weakness in its walls. Symptoms can be a pulsating sensation near the navel (you mention you feel a ball like object there), back pain, and pain in chest and abdomen.
You state your pain level when you move is a 7 or 8. While this could be anything from a muscle pull, to an ovarian cyst/ mittlesmertz (ovulation pain, often felt mid cycle), because the pain is so severe and could indicate something so disastrous, its not safe to assume its from a minor cause. I would get this pain assessed immediately, go to an ER....you've been in pain since yesterday, and quite a lot of it.
Please do go get this looked at, now.
Here is information on aortic aneurism: http://www.mayoclinic.com/health/aortic-aneurysm/DS00017
I hope I was able to help