@heisenberg34
It sounds like your weed whacking movements/twisting and vibration of the tool aggravated nerves that haven’t been irritated in a while. I have this happen to me when I do something new or when I do something I haven’t done in a while. I aggravate everything and pay a price for a while until things calm down again. The best you can do is stretch/strengthen core and limbs and warm up before doing any activities and not do too much at one time. Take regular breaks and work in smaller chunks of time. It may help to pre-apply nerve pain medication or patch and back brace to help control wide ranging movements.