She has never had kittens. But thank you for the input, I'll take her in to get looked atIs your cat currently nursing/recently had kittens? If so I would say something like mastitis, In which case you’ll need medication from a vet ASAP, as it can be incredibly painful and will lead to the mother preventing her kittens from nursing. If not you may want to take it in anyway as soon as you can as cats can sometimes get mammary tumours/carcinoma. The vast majority are malignant but in the unfortunate chance it’s not you’ll want to get him/her looked at immediately to start treatment in the early stages.