Why am I still feeling pain 15 years after an injection?

From monitor.co.ug/uganda/magazines

What you need to know:

• An X-ray, MRI or a CT scan to the back may show the likely cause. MRI, CT or ultra sound scan of the bum may also show the swelling in the bum that may be pressing the sciatic nerve.

15 years ago, I got an injection on the buttocks and there is a dent to show for it. Recently, the same area started hurting and when the pain starts, the down part of my leg feels as though it is paralysed. What could be the issue? Birungi 

Hello Birungi,

The body, apart from having nerves that work automatically, has two other main types of nerves called the sensory and motor nerves.
Sensory nerves carry signals from certain parts of the body to the brain so that one is able to feel pain, appreciate touch, taste, smell and sight. The motor nerves carry signals to the muscles to help them move.

A nerve called the sciatic nerve exits in the vertebrae (bones that protect the spinal cord) from the lower back to the bums, back of the thighs and calves to the feet. This nerve, therefore, helps the sensory and motor part of the lower back, the bum, thighs, feet and toes.

Previous scars that grow bigger, development of boils or other swelling on the buttocks that may press on the nerve may then cause pain and numbness in the affected area of the bum and legs such as what could be happening to you.

Surprisingly, even any bone growth- or age-related changes on the cushions or bones of the back may lead to pressure on your nerves resulting in the symptoms you are experiencing. 

An X-ray, MRI or a CT scan to the back may show the likely cause. MRI, CT or ultra sound scan of the bum may also show the swelling in the bum that may be pressing the sciatic nerve.

It is advised that injections such as quinine are given in a drip instead of on the bum to avoid injury of the sciatic nerve. Also, trained nurses or doctors should be the only ones allowed to give injections including those on the bums to avoid the likelihood of causing injuries to body structures that may be medically unknown to them.

https://www.monitor.co.ug/uganda/magazines/healthy-living/why-am-i-still-feeling-pain-15-years-after-an-injection--4506862