This is not really a lawn care question, but I figured you guys are more experienced to know. Lately, every time I use a edge trimmer to trim my lawn, My arm shivers for about an hour afterwards, and I feel weakness in the arm. This is only for about 30 minutes of trimming, using a relatively light weight electric trimmer. Anyone else have the same issue? I can't imagine if I do it as a business. Does it indicate some underlying health problems?