You may have a panic disorder, but your pain is still real. Some people who have no anxiety problems at all and can experience these same symptoms. People with panic disorders feel real pain even tho it is "self-inflicted" by the anxiety condition. There are medications that can help with anxiety and if you are not taking any, you can ask your doctor who should be happy to help you with that.
But.......
You can always sign up to see a different doctor. Some doctors can misdiagnose because they have a different school of thought. It's always nice to see someone else to get a second opinion to ease your mind about your diagnosis.
Even if neither doctor thinks that it is necessary or logical to schedule an MRI, they are not allowed to refuse you access to one if you request it. If it is not recommended for you, the only trouble you might have is insurance compensation, but the doctor should work for you on this.
Once you see the results however, you must accept what the doctor has to say after analyzing your test.
Best of luck.