1) Confined 2) Incarcerated 3) Kept inside 4) Ready to burst 5) Repressed 6) Unreleased 
[adj] - characterized by or showing the suppression of impulses or emotions
repressed adjective characterized by or showing the suppression of impulses or emotions; `her severe upbringing had left her inhibited`; `a very inhibited young man, anxious and ill at ease`; `their reactions were partly the product of pent-up emotions...