最も一般的な副作用は、注射部位の痛みです。

Meaning
the most common side effect is pain on the injection site

Vocab used in this sentence

最も
most, the most, best, least, farthest, extremely
一般
general, common, ordinary, customary, normal, usual, rife, habitual, unremarkable
a, mark, typical, target, objective
a, the, na, nan, nai
副作用
reaction, secondary effect, side effect, side effects, adverse reactions, adverse
a, the, is, am, are, will
注射
injection, injected, shot, vaccination, syringes
部位
part, position, site, section, portion, area
to, of
痛み
pain, ache, sore, painful, damage, smart, grief, distress, bruise, soreness
です
is, be, are, am, that, away