Can I have two majors?

It is certainly possible to simultaneously complete two majors.  You must be aware, however, of the difference between a "double major" and a "double degree."

A student may complete a double major by satisfying the requirements for majors in two different departments.  Both majors must have the same degree title, such as B.S. (Bachelor of Science) or B.A. (Bachelor of Arts).  A common double major is a B.S. in Computer Science and Mathematics.  No extra units are required for a double major, so a student could graduate with only 120 units, assuming that the course requirements for each major were met.

In order to complete a double degree, a student finishes two majors with different degree titles.  A common double degree is the B.S. in Computer Science with the B.S.E. in Computer Engineering.  In order to earn a double degree, students must complete 30 units in addition to the units required for the degree with  the higher number of units.  For example, the Computer Engineering degree requires 127 units.  In order to also graduate with a degree in Computer Science, a student would need to earn a total of 157 units.

If you are interested in adding another major, talk to an advisor in that new major department.