Pain under heel

Today during my FSs I felt a pretty sharp, located to a very small area directly under my heel, pain during the calf stretches, mostly the standing stretch.

Hopefully I have just hit my heel against a stone while surfing but I'm a bit worried it might be a beginning heel spur. I have never had one so I don't know how they feel.

I don't know what else in my life would cause a heel spur, especially since it hasn't before so do you think it would be possible to develop one from the calf raises and stretches in this program?

Obviously I skipped the hurting stretches today.

This is very difficult also with super tight calves tissue. Of course  you surfing situation could be the cause, try to stretch over a soft surface. and for the rest do not perform painful movements.