Hi there, mental issues aren't caused by a single reason but are multifactorial. Similarly, OCD can be caused by multiple reasons i.e due to genetic, environmental, causes etc. We cannot pin point the exact one reason which could have caused it.
Coming to the next part of your question about curing it. So, OCD is a disease which increases and decreases during different phases of life depended upon your mood, recent stress etc. It cannot be predicted that when it will be completely cured. Also, each patient is different and has a different course.
But yes, OCD can surely be managed by a combination of medications and psychotherapy.
Next Steps
Consult a psychiatrist if you are experiencing any symptoms and you think it might be OCD
Health Tips
https://www.practo.com/delhi/doctor/sharon-narula-psychiatrist