I hate these stories about the tragedy befalling someone because of missed medical tests. They are 'tragic' and the media picks them up and tells us about the tragedy and this poor person is going to die.
This is one about a woman in England who had breast cancer and now has brain tumors and was told that she has weeks to live. The media tries to blame this one on the health care system. I'm sorry and its a tragic story but still the patient should have done more on her part as well.
If you go to the doctor and they tell you its whatever - arthritis - and gives you medication. You take the medication and it doesn't work, you need to go back to the doctor and say this isn't working and demand more care. If its still a problem keep going back to the doctor until you are feeling better. If you still are refused care, find another doctor. You can't sit there and let them tell you its nothing if its something that gets worse.
I'm such a patient patient, I would be hanging out in my doctor's waiting room and getting more opinions to find out what is wrong.
Being a patient is a two way street. If you go to the doctor, you need to listen to their instructions and avoid them at your peril. If you follow their instructions, you should expect to feel better in the long run. On the other hand if you go to the doctor and follow their instructions and don't get better or achieve the expected results, speak up and demand more. Don't sit back in pain or discomfort and let them tell you its nothing.