What problem do i really have. This.

Hello, My Tsh levels are really high ranging from 56uiu to 12uiu for several months and i am on thyroid medicine levothyroxine from last 6 to 8 months. I have got an ultrasound scan done for my thyroid glands, and it shows that both of my glands appear bulkier in size, lobulated appearance with heterogenous echotexture and the final impression of the scan report states that i have THYROIDITIS. I would like to know what can be the actual reason for such high tsh values and thyroiditis with high cholestrol (cholestrol is high since i got my thyroid problem) and what is its causes as i have no family history of thyroid and no personal disease history as of yet. It would be a greaf favor if anybody would be able to answer this. Thankyou.