During its replication cycle, viral capsids undergo various transformations going from protein self-assembly to disassembly. The micro-environment is thought to play a major role in triggering these transformations. In this work, we review the current understanding of the correlation of viral capsid molecular stability with its physical and chemical environment. In particular, by analyzing the forces that act on capsid proteins and the ways in which they are held together, one can gain insight into how capsids maintain their structural integrity under different conditions and how they may be affected by external perturbations such as mutations, drug treatments, or mechanical triggers.