I googled these two lines and found them appearing in the lyrics of a song called Keelatud maa ('forbidden land, forbidden country') by Maarja. Is this where you heard them? I'm asking because the first of the two sentences (on its own, without further context) can be interpreted in many different ways:
Sel keelatud maal, ma tunnen end siis
- sel = on this (allative)(sometimes corresponding to 'in' in English)
- keelatud = forbidden < keelama - to forbid
- maal = land (allative)
- ma = I
- tunnen = I feel, I'm feeling < tundma = to feel
- end = reflexive pronoun (often untranslated in English)
- siis = then
--> In this forbidden land, I feel (myself) then (?)
The second sentence is clearer:
Sind otsin ja jälle me vahel on piir
- sind = you (partitive - an object case)
- otsin = I search, I'm searching < otsima = to search
- ja = and
- jälle = again
- me vahel = in-between us (vahel is a postposition)
- on = is
- piir = borderline, frontier
--> I am searching you and, again, in between us there is a frontier
Perhaps native speakers can help...