Two large lumps in butt cheek. First no pain, but burning pain has developed & runs down leg

found

two relatively large ball like lumps inside my left butt cheek. No pain at first than 2 weeks later the skin above the lump became painful to light touch and then the pain started running down the lateral side of the same leg. They appear to be getting smaller , but still have much pain. What can this be? Shingles? I started taking my sisters valacyclovir 1 gm every 8 hours . and they seem to be getting smaller, but still painful