This paper aims to develop a system for automatically assessing the pain level of chronic pain patients. We propose Tiny-BioMoE, a lightweight, pre-trained embedding model that utilizes various biosignals (electrodermal activity, pulse, respiration, and peripheral blood oxygen saturation). Trained using 4.4 million biosignal image representations, Tiny-BioMoE consists of only 7.3 million parameters and demonstrates its effectiveness in extracting high-quality embeddings for downstream tasks. Experimental results on various combinations of biosignal modalities demonstrate the model's effectiveness in automated pain recognition tasks. The model's architecture code and weights are publicly available.