Cold is one of six climatic pathogenic factors (ie. a quality in the environment or climate which can cause disease). Not only can it cause the common cold, but also many other illness such as arthritis, stomach pain and breathing problems etc.
Cold is the dominant climatic factor in winter and so cold diseases, although also encountered in other seasons, are usually seen in winter. When cold attacks the body, it tends to impair the yang principle and lead to yang deficiency. Cold tends to coagulate and contract, so it often causes pain symptoms.