Hey Shobhit, Solo trips near bangalore are many of them ... Here are few for you - Coorg Hampi Lepakshi Mysore Savandurga Manchinbele dam Nandi hills Bandipur Ooty Masinagudi Happy Travelling Bro!!!
Hi Shobit, here is a list of destinations you can visit from Bangalore
Mysore
Hogenakkal
Yelagiri Hills
Horsley Hills
Chunchi Falls
Sangama & Mekedatu
Bannerghatta National Park
Also, i'm attaching with this comment a post that will guide you about more places to visit around Bangalore.
Coorg would be the best option . you have Abbey falls , irupu falls , still water rafting , elephant camping , bhylakuppe monastery . It ll be a perfect for a two or three day trip .