My mum had abdominal surgery, and one night following the surgery, she felt an extremely painful tear sensation in her lower abdomen and shortly afterwards noticed a big asymmetric lump in the intestinal area.
My partner is an ICU nurse and suspected a hernia so we took her to the local hospital and the doctor said it's just post-surgical swelling. It didn't go away, rather it got bigger, more painful and frequently gurgled, so we went to the GP. The GP said it's probably just because she's had kids 30 years ago (!?) and that my mum needs to get used to not looking attractive any more, and to lose weight.
What followed was months of doctors visits trying to get them to even accept there was even an issue. Bear in mind, this was a significant, painful gurgling lump, around the size of a tennis ball. Yet doctor after doctor said there was nothing wrong with her and she should consider therapy and antidepressants instead.
After a few more months, she began experiencing such bad pain that she couldn't walk, and finally a junior female doctor suggested she had a hernia. However, she got overruled by her senior and sent home with paracetamol. The junior doctor quietly told her to go to another hospital.
We managed to convince my mum this was ridiculous and brought her to London, where she got looked at by a hernia expert, who was very concerned about her treatment thus far and sent her for a CT and - obviously - found a large hernia. Due to the time it was left untreated, the repair was very challenging with many complications.
Back home again, while recovering, she was having the early warning signs of an infected surgical wound (hot swelling, pus, smell, chills etc.) and again the local hospital fobbed her off and said she's overreacting, didn't swab the wound or change the dressing and sent her home. That night, she called me incoherent and I called for an ambulance - turns out she had sepsis and nearly died.
I can promise you that we made sure everyone treating her had a full medical history at every point, but they still blatantly ignored what was right in front of them. There is actually a ton more to this too - the surgery in the first place which triggered all this was due to a medical error and wasn't necessary. It's been five years so far.
She's currently suing the local hospital and doctors.