Hello, I am quite empathetic to your sun burn problem over legs, arms and chest. It is apparent from your query that you have recurrent tendency of sun burns. In most of the patients with your kind of problem I suggest to avoid direct sunlight. I also advise to do cold compression over all the affected areas over legs, arms and chest. In my patients with your type of condition I advise them to use an antihistaminic tablet such as loratadine or levocetrizine for two times a day. It is quite very useful if a mild steroid lotion or a calamine lotion is applied which helps in decreasing the burning sensation. Eat a lot of green vegetables and red fruits which acts as natural sunscreen factor to prevent sunburns. All the best.