I have recently inserted a mirena. can it be the cause of me having a hip pain when exercizing?

Maybe. Maybe not.: One can look at everything that occurred from about 3 weeks before Mirena until the hip pain started. What sort of exercise routine was one doing earlier, compared with after Mirena? Include looking at the pre- and post-exercise stretching and care. Any changes in type or amount of exercise. Any unusual body positions... such as flexing or rotating flexed hips a large amount while getting the IUD.