See an eye doctor. Vision symptoms after cataract surgery can have various causes. If the symptoms have only recently appeared, it may be a sign that the capsule where the implant is sitting may be clouding up, and a simple procedure in the office will cure it. If the halos have been present ever since surgery, you should have an exam to find out the reason.
Can happen! Depending on what other issues with the eyes exist, this can happen. If there has been some previous corneal surgeries such as rk or laser eye surgery (lasik) his can happen. Also the compatibility of the wavefront of your eye and the implant is another issue. Suggest seeing your surgeon. You may have also started developing posterior capsular fibrosis which may easily be lasered clean!