I recently had a CT scan and they found spots on my liver, what could this be. Having another CT scan w/contrast next week?

It depends. It depends on several things. The most important considerations are age, sex, and other medical problems. In broad terms, these spots could be anything from cysts to hemangiomas (abnormal, non-cancerous blood vessel accumulations) to cancerous tumors. The ct scan should help clarify. Sometimes a biopsy is necessary to confirm the diagnosis if the ct is unclear.
CT scan. Liver spots following ct can be benign such as: hemangioma, liver adenoma, and a granuloma. Cancer spots diagnosed with ct can be liver cancer or metastatic liver cancer.
Many things. A "spot on the liver" could be many things. If you have no history of cancer anywhere, the most common things could be a simple cyst (benign fluid) or a hemangioma (benign collection of blood). These would be the most common. Other causes could be a primary tumor of the liver or a tumor that spread to the liver from another location. The contrast exam will help them characterize the abnormalit.
Multiple things. "spots" on the liver on a ct scan can be numerous things, most of which are benign. The most common things are simple cysts or a benign vascular lesions such as an hemangioma ( a collection of blood vessels). It is sometimes necessary to do further studies such as contrast ct, ultrasound or MRI so a malignancy can be excluded. All or none of these tests may be necessary, depending on its appearance.
Many things. Spots on the liver can represent many different things ranging from benign cysts and hemangiomas to tumors. A ct without contrast cannot tell the difference between them easily. Both benign problems and malignant problems are common.