Welcome to HCM.
The commonest cause of an enlarged clitoris
is increased secretion of androgenic or male hormones. Disorders of the adrenal glands
or treatment with steroids
may also cause clitoromegaly
If hormones lead to clitoromegaly, they also usually disturb the menstrual cycle. It seems from your post, that the size is enlarged to the extent that it is interfering with your routine activities like sitting.
From your case it appears that you have noticed this for the first time. This indicates that the problem has developed recently and is not present since birth. Hence it is more likely to be treatable.
I recommend that you consult a gynecologist and get yourself evaluated. A surgical correction may be required depending upon the extent of the problem.
Hope I was able to help you. Enjoy good health..