He took an OTC indigestion remedy, and his pain eventually resolved after a couple of hours.
 His pain improved after taking an over the counter medication
(ROOT (S (NP (PRP He)) (VP (VP (VBD took) (NP (DT an) (NNP OTC) (NN indigestion) (NN remedy))) (, ,) (CC and) (NP (NP (PRP$ his) (NN pain)) (VP (ADVP (RB eventually)) (VBN resolved) (PP (IN after) (NP (NP (DT a) (NN couple)) (PP (IN of) (NP (NNS hours)))))))) (. .)))
(ROOT (NP (NP (PRP$ His) (NN pain)) (VP (VBN improved) (PP (IN after) (S (VP (VBG taking) (PP (DT an) (PP (IN over) (NP (DT the) (NN counter) (NN medication))))))))))
( He ( ( ( ( ( took ( an ( OTC ( indigestion remedy ) ) ) ) , ) and ) ( ( his pain ) ( eventually ( resolved ( after ( ( a couple ) ( of hours ) ) ) ) ) ) ) . ) )
( ( His pain ) ( improved ( after ( taking ( an ( over ( the ( counter medication ) ) ) ) ) ) ) )