The investigators propose to test the efficacy of the PTSD Coach app vs. treatment as usual (TAU) among a sample of acute physical injury patients, to: 1) Determine engagement with PTSD Coach, by measuring frequency of use over 4-weeks and assessing ratings of usefulness and qualitative feedback: it is expected that >80% of PTSD Coach users will use the app at least once a week, and will rate it as at least somewhat helpful; 2) Estimate effect on CP symptoms by measuring PTSD and pain intensity at 1- and 3-months. The effect of the intervention on pain interference, disability, and coping self-efficacy will also be explored.