Lots of people just dread the spinal tap (Lumbar Puncture) because of how horrifying it sounds! But I can tell you from experience, it's all just a bunch of talk. It really depends on the skill of your doctor. My first LP was "shocking" because my doctor did not seem to have a steady hand and she hit a nerve. My last LP? I hardly felt it!
I know these test may sound scary but they are not. An MRI is really only bad if you are really claustrophobic because they slide you into a sort of tube and you have to stay steady while the machine is running. They will probably offer you medication to help you relax but I have never needed it and I am pretty claustrophobic. The machine makes lots of loud buzzing and beeping sounds which are kind of funny, I have a hard time not smiling like an idiot while I am in there. A brain scan might take around half an hour to an hour depending on if they are doing scans with contrast or not or depending on how detailed of an image they are trying to get.
A lumbar puncture only sucks if your doctor sucks! Well that and if you don't drink enough fluids and lay down for at least 24 hours... Use this time to wat TV, a movie, more go on a Netflix binge!
Don't let the answer you may get or the tests you have to do scare you away... If you put it off it will only get worse in the long run and the unknown of your situation will torment you. Treat it like a bandage, the quicker you rip it off and get it over with the less pain it will cause. The sooner you get an answer the sooner you can find a solution.