Esther Lowery, 17, from Holywell, suffers from Ehlers-Danlos syndrome, a genetic condition which means her body tissue is not strong enough to hold her limbs in place.
She calls it an "invisible illness" because the symptoms go unseen by others.
Esther can walk short distances which has led to her being branded a "fraud".
But she experiences "agonising pain" when her elbows, shoulders and knees pop out of their joints up to six times a week.
"When I go out to museums or go shopping and I know it's going to be a long day, I'll use my wheelchair", she said.
"But say if it's just walking to the house from the street, I can make it without crutches or a wheelchair, so I think that's what confuses a lot of people when they see me get out of my chair and start walking.
"I remember walking up a couple of steps once, and when some people saw me getting out of my chair they shouted 'it's a miracle!'
"I was really upset because they have no idea how much pain I'm in on a day-to-day basis."
Esther has made a three-minute documentary to raise awareness about the condition.
A teenager from Flintshire has been accused of being a "fake" for using a wheelchair to cope with a rare illness.