Lower left side neck pain and stiffness.

I have 3 issues, 1. I get pain on left side of lower neck near to trapezius. it's on and off from last 10 years .. i just rest and it gets better .. sometime i don get pain at all for few months and sometime i get frequently . it's intermittent. 2. After my delivery from c section which was 1.5 years back i feel tired in neck and shoulder area .. i keep lifting baby to take care .. my b12 and vitamin D is fine as i have taken supplements . 3. my hands also feel weak from last 6 months .. can't hold baby for long or lift anything for long time .. i am a software engineer and most of my work is in front of system why is this happening .. ultrasound physio therapy didn't help .. consulted ayurvedic treatment that's also did t help much