I cannot confirm anything without examination,but they can be baker’s cysts or lipomas.
A Baker's cyst, otherwise known as a popliteal cyst, is a benign swelling found behind the knee joint. Diagnosis is confirmed by examination, ultrasonography and MRI.Lipomas are benign fatty tumors.
In my opinion getting them examined by a orthopedician will be the best.
Hope it helps.Take care and pls do keep me posted on how you are doing and if you have any additional queries.