Many. Possible nonunion, infection, nerve or blood vessel injury, avascular necrosis of the femoral head. It is major surgery with many possible complications. Find a specialist who does this procedure frequently.
Oh yes. An osteotomy of the hip will likely be painful and your surgeon will likely give a fairly strong prescription pain medication. Certainly, different people feel pains differently. A positive outlook can significantly improve patients' perception of their pain.
You should. Most surgeons use narcotic, oral pain medications after those types of procedures.
Replacement. There are very, very few indications for an osteotomy in this day and age. If the arthritis is bad enough, replacement is usually the most reliable choice.
A hip or 2. You have not specified the reason. My experience dictates that an osteotomy will end up with a thr. Get a 2nd opinion.
THA vs osteotomy. Experience and recommendations of your hip surgeon. Localized arthritis with well-preserved surfaces may be better served with osteotomy, if a congruent, well-contained result is possible. Significant joint erosion and deformity will likely fare better with tha.