Not only HS-CRP but also WBC, erythrocyte sedimentation rate (ESR), and plasma viscosity (PV). Your ferritin level can also be an indicator, I understand. An analysis of lipids might also tell someting (e.g. levels of arachidonic acid or ω-6 fatty acids).
The reaction to casein and/or whey protein can take various forms, but often it is an inflammatory response, similar to the gluten reaction.
Joint pain, swelling, and arthritis-like pain are also symptoms of systemic inflammation.