そば means 'near' or 'beside' and is used similarly, but 側近く is a compound noun that can stand alone as a location, whereas そば is often used with particles like に or の.
Standard kanji spelling using 側 for 'nearby'.
Mixed kana-kanji spelling; common in informal writing.
Alternate kanji using 傍; less common than 側.
Formed from 側, “vicinity,” and 近く, “nearby,” emphasizing a location close at hand.