A few months ago I started getting really bad back pain. Some mornings it just hurt to bad to even move when I woke up, let alone trying to do something like sitting up. All the pain was in my middle to upper back...into my neck and shoulders.
The back pain has since went away, but now I am experiencing pain off and on in my left shoulder and down my arm. I also get intense tingling sensations in my left arm and left hand. My pointer finger and middle finger are constantly numb and when anything touches them it feels like intense pins & needles sensations.
I don't have any kind of condition with my back, I am 28 yrs. old and completely undiagnosed.
The pins and needles, pain and numbness can come from a nerve that is pinched. It can be pinched in your spine, but you can feel symptoms in your arm, radiating along the path of the nerve. That can happen from a herniated disc or other things.
It sounds to me like it could be a pinched nerve, maybe in your cervical spine. Especially if you have numbness & pins & needles in your arm. Spine problems in the upper back/neck area can also cause shoulder pain. And all the pains dont necessarily always occur just in one spot, they can radiate all over the place. There might have been a disc herniation that first caused muscle spasms in your uppper back (spasms usually occur to protect some sort of injury...though you need not have had to actually injured yourself that you are aware of). It could be simply bending or twisting the wrong way, or picking something up incorrectly.
You mentioned you dont have any back problems, but have you ever had it checked by a doctor..or had any x-rays or mri's done? If you havent, then my advice is that you probably should, especially if it lasts more than a couple weeks and/or is starting to affect your daily lifestyle. Any time you have numbness with pins & needles is definitely nothing to fool with. Not to scare you, but it's better that you find out what is causing it when it's still early enough.
I will definitely get a doctor's appointment ASAP.
I feel like I'm following in my dad's footsteps...he has back problems, too, but his affects his lower back and legs. He's currently receiving back injections for some ruptured disks and arthritis in his back.