Can Multiple Sclerosis and Arthritis Get Mix up?

I found out from my doctor that I might have Arthritis and we did blood test and they all came back normal. But my mom doesnt believe the test are right so were going to Get a MRI in July. My massage thearpist who's been helping me told me to write all my symptoms down and I did and she told me I could have Multiple Sclerosis because I have alot of the symptoms. I want to know if Multiple Sclerosis and Arthrtis can get mix up.I'm 14 turning 15.
here is all the symptoms:

-All my joints hurt (Hands,legs,elbows,ect)
-Vision goes blurring
-I feel like I'm unbalanced.
- I have trouble going up and down the stairs. I have a hard time holding coffee cups and at one point I cant even lift at all.
-I feel very tired and often at weird times can start to fall to asleep,even tho I've had plenty of rest and it like in the middle of the day and about fifteen minutes later I can be totally fine.
-I feel like pins&needles.
-Jaw hurting
-i sometime freeze at the spot.

Usually, a patient is diagnosed with multiple sclerosis between 20 and 50 years of age, but multiple sclerosis has been diagnosed in children and in the elderly. Multiple sclerosis is twice as likely to occur in Caucasians as in any other group. Women are twice as likely as men to be affected by multiple sclerosis earlier in life.

MS has a wide range of symptoms. Common symptoms: Visual disturbances may be the first symptoms of multiple sclerosis, but they usually subside. A patient may notice blurred vision, red-green distortion (color desaturation), or sudden monocular blindness (blindness in one eye). Muscle weakness with or without difficulties with coordination and balance may occur early. Muscle spasms, fatigue, numbness, and prickling pain are common symptoms. There may be a loss of sensation, speech impediment (typically a problem articulating words), tremors, or dizziness.

It may take months to confirm a diagnosis and rule out other causes. Tests are done to look for MS and to rule out other possible causes. Some diagnostic tests used are:
Blood work - look for Vit B12 deficiency and Lyme disease markers
MRI scans with intravenous gadolinium - identify and date lesions (plaques) in the brain. Newer lesions show up brighter.
Evoked potentials - hearing, vision, and motor impulses are tested to see if they move normally or too slow.
Spinal tap (lumbar puncture) - cerebro-spinal fluid is tested to identify cells that suggest MS. Can also be used to differentiate from Lyme disease.

For a definite diagnosis of multiple sclerosis, at least two separate symptomatic events or changes on MRI and a physical indicator (i.e. change in the central nervous system) must occur.

You need to see a neurologist (preferably through a Movement Disorder Clinic or an independent neurologist specializing in movement disorders) for a full workup. Your symptoms could be due to a variety of conditions - either due to drug side effects or because of some disease process. Seeing a specialist will help to ease your anxiety - to rule out things and/or confirm a diagnosis.

Are you on any medications right now? They can eventually cause these side affects as well.

Are you eating any of the artificial sweeteners from the blue, yellow or pink packets? If so, they can cause these symptoms over long term use as the number one complaint to the FDA is Aspartame from diet drinks and these symptoms are the same, so if you stop all artificial sweeteners it takes up to 70 days to reverse the symptoms.

Are you eating correctly, like your hunter gatherer anscestors, your body is the same and has the same requirements. Such has whole foods, nuts, seeds, raw fruits and vegetables, whole grains and no junk foods.

Much needs to addressed as to the cause. The diagnosis and course of treatment is your doctors job... The cause of the problem is to self educate.

Take care.