When I do squats, my left anterior forearm muscles tend to tighten up quite significantly. When flexing the wrist there is pain in the hand below the ring and pinky fingers. This has been ongoing for about two months and I am still playing around with my grip on the squats to try and find a good hand placement. The wrist is also painful when doing bench presses as well, with or without wrist wraps!
The latest development over the last 7 days is that when I wake up at night my hand is numb from that part of the wrist right up to the tip of both the ring and pinky fingers. All of this occurs only in my left hand and arm, no issues with my right side. I am right hand dominant.
What you are describing is called Ulnar Tunnel Syndrome and it is likely that your symptoms are a result of your grip on the bar when performing squats. Make sure that your back is carrying the weight of the bar instead of your hands, which are only meant to keep the bar in place. This should alleviate both your wrist and forearm symptoms.
I second this. I suffer from ulnar nerve entrapment/ tunnel syndrome, and you do not want your arms/ wrists taking weight of the bar. Alan Thrall has a great video on low bar, see: https://www.youtube.com/watch?v=xrnq4OAN5bE