If the post you're looking for is older then 7 days you can use SEDE. For example this query will search the Q/A pairs you participated in for a given word.
;with allQs as
(
select coalesce(parentid,id) as postid
from posts p
where owneruserid = ##userid:int?393087##
)
select id as [Post Link]
, owneruserid as [User Link]
, creationdate
, score
from posts p
inner join allQs q on q.postid = p.parentid
where p.body like '%' + ##search:string?database## +'%'
and p.owneruserid <> ##userid:int?393087##
union
select id as [Post Link]
, owneruserid as [User Link]
, creationdate
, score
from posts p
inner join allQs q on q.postid = p.id
where p.body like '%' + ##search:string?database## +'%'
and p.owneruserid <> ##userid:int?393087##
When run today this will be your result:
Keep in mind SEDE is only updated once a week.