right arm elbow shoulder weakness

Pardon the long intro i just want to be as concise as possible.  Im 19 now but my whole life i've exercised
alot.  I was always the strongest most muscular guy at school "naturally"( never
used steroids in my life)  .  Between either january
or february to june 2006 i made the most strength and muscle gains of my
life.  It was insane i was gaining 5 pounds on my benchpress a week every week.  
annd everything else was jumping in bounds also.  Everything was amazing untill
halfway thru june(this was in 2006 btw)when i was about to bench 275 pounds and
from the way things were going i should have achieved it and i believed my left
arm could have achieved it but my right arm just lagged and couldn't get to the
top even though my left could.  Stupid me kept trying once a week for weeks to
do it again but it just seemed my right arm would get weaker but the left was still normal.  It seemed to
be my elbow and whenever i tried to exercise that arm in any way it just seemed
to get weaker. so i realized that i had to start treating it so i have
practically layed off weight training for the passt 2 and a half years(since
june 2006).  During that time in the same arm i have developed a shoulder
problem.  My shoulder feels weak with repetitive motions or exercise and
ocassionaly i get a muscle fast twitching just under my rear shoulder/ in my lat area.  It seems
my arms can start bothering me / go numb if i lay with them behind my head.  My
arm just has never been the same and it seems something is deff wtrong.  i went
to an orthapedic had xrays and mri's taken and they couldn't figure out what was
wrong. i even did physical therapy for my shoulder and nothing helped..I have
had plenty of stints with anti inflmamatory medicines and long periods without
using my arm for anything besides regular daily activities. I even wore various
types of braces.  There was also many months where i stretched my entire body alot.  
Nothing has seemed to help at all.  This occurence has totally changed my life:
i had to quit sports, working out which was what i was known for, simple normal
activities i think twice about because it will bother my arm.  I want to join
the national guard too but i don't want to because i know the more pushups i do
the less i will be able to do the next day with my right arm.  and these days im
not totally sure but i've had some slight thoughts that my left arm might start
this and i've been suggested by friends  that it could be a neck or nerve
problem

[Aroc718]

i had similar problems from earlier in life... used to be able to work out a lot... was very strong for my build.. all of a sudden it went downhill when i felt i was in my prime and these acut (acute) changes in my muscular strength were signs of a motor nueron disease... u need to get this checked out asap.. and avoid surgery at all costs... it can damahge ur nerves and muscles even further than you ever dreamed