Changes at work have also been building up quite a lot of stress.

Literal

Workplace/work [possessive-の] changes [with-で], considerably stress [subject-が] is-accumulating [nominalizer-の] [also-も] exists.

で marks the cause: changes are what's producing the stress. ~のもある means 'there is also the fact that,' presenting this as one factor among several. ストレスがたまる (stress accumulates) is a common collocation. The mid-dot ・ between 職場 and 仕事 lists related terms.