I get them too. Always have since my Pn. Sometimes they can be very bad. Magnesium helps me but modestly. Last week I woke up in middle of night with cramps in both calves. It felt like my legs were broken it hurt so much. For 3-4 days afterwards both calves were really sore.

The only thing that works for me short of taking a pill is doing leg stretches at least twice a day.

I wonder if the muscle is so tight and cramppy because it's shortening due to PN?

Anyways I don't know the answer LJ, but I can empathise.