Hello glenn**** thanks for your question the symptoms you are experiencing are cold, headache, coryza and fever for two days and while laughing and coughing you are having pain lower left back. Friend first of all I would like to tell you that its very rare to have enlarged spleen in a viral fever of 2 days, the pain is not due to spleen enlargement. Then what is the reason of the pain? In common flu or cold which is a viral infection we are not able to remain active and are usually bed ridden, this usually leads to fatigue in muscles and also during continuous coughing straining of rib cage muscle and back occur which causes pain on exertion. So its fairly normal. Secondly some times in viral infection or after secondary bacterial infection a little of fluid get collected in pleural cavity which can also cause pain in back, but such type of pain is usually rare to develop in 2 days and also the pain is sharp stabbing type, so you need not to worry. If pain don t improve then you can use one or two doses of any OTC analgesic. take care and take good nutrition. thanks hope i solved your query kindly rate.