Clear liquid is likely not anything huge, however, since you are also having pain, get it checked out. You could have an infection. But in general, women emit nipple discharge due to hormones. I had prlactemia which is a name for this as a chronic condition. Don't be afraid to see the doctor . . . this is not an unusual problem for them and this is likely not a super serous issue. Could you be pregnant? Are you on the pill?.