A couple of friends of mine have been diagnosed with spondyliosis - small bones growths on various vertebrae or just one to start with. You should definitely go to the dr if you feel a lump. if it is bony growths, things can be done, but if left, the vertebrae can fuse and then you get more problems. Also the direction of the growth is important as they can grow in towards the spine sometimes and sever the cord. Not that it sounds like this is happening for you, but it is a risk if you know nothing about it and leave it unattended. It is a form of arthritis I think.
Good luck.
Thanks for the post and information. There is not any additional symptoms as you mentioned and the bump feels like it may be part of the bone or a growth on it. I'm really hoping I just happened to bruise it somehow. I have an appointment in a couple of weeks so I'll get it checked out.
Again, thanks for the information and your time.
Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with your doctor.
Without the ability to examine you or obtain a full history, I can not make a specific diagnosis but I will try to provide you with useful information. From the description you give it sounds like the type of pain or discomfort you have is localized only to the area and does not move down one leg or another or cause any numbness anywhere else. Additionally you don't mention any loss of bladder or bowel control. You also don't describe back pain per se, but perhaps a more superficial pain. Accordingly, it sounds like this is less likely related to the spinal cord itself.
Instead you describe pain localized to a small bump. It would be important to know if you have any additional symptoms such as fever, chills, nightsweats, weight loss, or confusion. It would also be important to know if, on examination, you have any discharge from the area or any redness. It sounds like there is swelling. Many of these features suggest inflammation. Although difficult without more information to give you a complete list of possibilities, one that is very common and most often occurs on the upper portion of the buttock is known as a pilonidal cyst. These can occur when a small hair blocks up a sweat gland and can cause significant swelling and discomfort.
A GP or family doctor would probably most appropriate to see first for this problem. After a more thorough history and exam, he/she may order some routine blood tests to look for inflammation and may want to do some imagining. If this is a pilonidal cyst, treatment may include antibiotics, hot compresses, and often a small surgery to drain the infection.