Hi and welcome to the board. I am sorry you are feeling so badly. We do have occassional members that are diagnosed without lesions but remember that "multiple sclerosis" does mean more than one scar. The current criteria leaves it up the doctor - so a doctor can diagnose you without lesions but it is assumed that those lesions will then show up in the next two to three years. If they don't, then it is highly recommended that the diagnostic proceedure starts over.
Certainly a lumbar puncture at this point is helpful. It can indicate many things that mimic MS. And you should be researching all the diseases that mimic MS. Google "diseases that mimic MS" as a place to start. You may also want to post your symptoms on our Lyme disease board because of the shared symptoms. The pain in your hips and groin is not a typical one for MS, and most doctors don't look at ANA for MS.
Good luck. It appears you will be off for a second opinion. I hope you find some answers real soon. Please ask as many questions as you like and again, welcome to the board.