Sharp temporary pains in ovaries plus shivering, 1 week pp

Rosie

I've felt great since my unmedicated, straightforward vaginal birth one week ago. This evening however I had a half hour of sharp abdominal pains (felt like ovaries?) and uncontrollable shivering. Very distinct to my previous afterbirth pains (which were more like dull back aches). Has anyone experienced this? Is it just hormones adjusting? It was unpleasant!