Rec for Cat fur tearing please

Hi,
My 12 year old long haired cat who is an 85% indoor cat in relatively contented and good health had an accident of being hit by a car nearly 3 years back. The result was a femur and leg injury. It was all fixed up at the vet though and she was better after 4 weeks and back to her old self. The vet had to shave the area and she was very, very upset about that. Since this time she has been pulling the fur out in this area and chewing on it. It's balding. I cannot figure out what is going on. Her environment is controlled, so I am thinking it may be from the past trauma. As I said, she is in good health. Her only current issue is constipation which the vet has attributed to age. We treat that with fibre and pumpkin supplement. She has a healthy appetite and regularly shows gratitude after her meals. Her natural disposition since she was a kitten is a scaredy cat. Every sudden move frigthens her. She also dislikes any loud noise. She loves her own people, but not strangers. She seeks out people's company but is more of a 'side cat' rather than a lap cat. She DESPISES other cats. That's why we've decided on not having another one here. She does not handle heat well and seeks cool areas when the climate turns warm. She does not do well with enclosed areas and all of the doors of the home have to be open for her. Closed doors stress her out. She likes play, although tires quickly. She scratches furniture when excited or when trying to get my attention. She likes to get a rub from me in the morning for 20 minutes which has become a routine of ours. She wants time with me alone, which means without my spouse around.