Probably, getting ready to cut some teeth. Excessive drooling is also a sign. But, would be best to ask their pediatrician. If they are tugging at their ear could be an ear infection, which may not be evident, without an exam. Fever usually means infection, marked with green or yellow mucus. I have written a hub is it cold or allergy? On the subject. I hope this helps.
It could be many things. Ear infections are notorious for not having symptoms for some while also causing a fever. There are other possibilities such as a urinary tract infection. Depending on the severity of the fever, a visit to the doctor would be a good idea, especially if you don't know what is causing the fever and if it continues.