Thank you Adeel for asking the question. 
Ankylosing spondylitis is disease in which vertebrae fuse together, which result in pain and decreased flexibility of the backbone. The onset of disease occurs in early adulthood, as you were 21-year-old when your disease started to show itself. The cause in unclear, but a genetic factor is the most common predisposing factor. If your father, mother or in their family someone has joint problem or joint disease then this increases the risk. 
Now, as you are already diagnosed with it, here is my opinion on it. 

In ankylosing spondylitis, the aim of a doctor is to reduce the symptoms, that is pain, here our main goal is pain relief, as there is no definitive cure of this disease.

• first step is to give pain killers, pain killers that are usually given include, NSAIDs, eg., diclofenac, meloxicam, etc.
• Physiotherapy should be continued, as it delays progression of disease, relaxes muscles and help in decreasing the pain and maintain flexibility.
• If NSAIDs stop helping, then TNF inhibitor drugs are tried, for example Etanercept, infliximab etc these are little costly. 
• Sometime if pain is not controlled with above measures, then your doctor may suggest injection that are directly administered to backbone, these give relief for few months. 
• If nothing helps surgery is done, but usually patients need this later or not at all. 
• Improve your diet, take vitamin D and calcium tablet daily, so that your bones remain healthy and osteoprosis can be avoided. Continue physotherpay. 
• Monitor yourself for signs and symptoms such as blurred vision, rapid heart beats, dizziness etc. if any of these symptoms appears see a doctor immediately. 

An orthopedic or spinal surgeon is a specialist you should see and also take consultation from a rheumatologist. You should come to Capital to find a specialist who can actually help you. If you have a further question, then you will need to register on this website, then you will be able to reply to this answer. 

Best Regards. 
Dr. Adil Ramzan