All breast implants will form a scar capsule around them, however in a small percentage of patients the capsule will tighten and the implant will round up and become firm. It is not uncommon to see the capsule form on only one side. Typically the implant will be soft and symmetric, and slowly during the first year or two the firmness will begin. It is unusual for an implant to start out that way, though it can happen. If the capsule is tight it can be released and opened in a procedures called capsulotomy. The implant will soften nicely though the recurrence rate of a firm capsule is 50%.
It may be possible that your implant was not placed symmetrically and if it was never soft and even with the opposite breast, reshaping and lowering the pocket may solve the problem as it was not a capsule contracture at all. I hope this is your situation as capsule contracture can be a recurring issue.
Best of luck,