Why do i have brown spots on my legs?

Lentigines: I think you are likely referring to lentigines (plural for lentigo) which are caused by the sun damage.

Wouldn't be able: to accurately diagnose this with this amount of info. These lesions need to be visualized & a history needs to be obtained in order to make an accurate diagnosis.

Hemosiderin: This is a pigment in the blood that may deposit itself on the skin leaving brown lesions. Usually this is caused by venous stasis or the blood not being able to return to the heart from the legs. Keeping the legs elevated to the level of the heart may help, decrease swelling of the ankles if it is present.