Christopher Still was a Private during the Revolutionary War, according to Ancestry.com. (1)
In 1789, a Christopher Still appears on Pikeland's Tax and Exoneration List. (2)
In 1799, a document regarding his death was filed in Chester County. At that time, it reveals he lived in Vincent Township. The administrator of his account was John Evans, also of Vincent Township. (3) He died intestate. (7)
Christopher Still is also listed in the American Genealogical-Biographical Index however Ancestry.com does not reveal the full text at this time. It does reveal he was born in 1750 and that he is mentioned in Volume 169 on page 183. (4)
Another source lists a Christopher Still as a Corporal receiving a pension. He began receiving it in 1785 and died 22 July 1807. He had received an annual allowance of $48 and a lifetime benefit of 432.13. (5) The Corporal Still shows up again in the "Vol. II. Muster rolls of ranging companies, &c., with lists of Pennsylvania pensioners in 1789 and 1813." It reveals he mustered out in March 1798. Assumedly there were two Christophers then.
A Christopher Still was injured during the War. The wounded Still was under Captain Christie's command and was wounded at Brandywine. This source shows he was discharged at Valley Forge in 1778 and resided in Chester County. (6) Since I already found documentation that the Colonel mustered out in 1798, I feel safe in considering the wounded Still to be the Private.
(1) Ancestry.com. Pennsylvania, Revolutionary War Battalions and Militia Index, 1775-1783 [database on-line]. Provo, UT, USA: Ancestry.com Operations, Inc., 2012.
(2) Pennsylvania Historical & Museum Commission; Records of the Office of the Comptroller General, RG-4; Tax & Exoneration Lists, 1762-1794; Microfilm Roll: 321.
(3) Ancestry.com. Chester County, Pennsylvania, Estate Papers, 1714-1838 [database on-line]. Provo, UT, USA: Ancestry.com Operations, Inc., 2013.
(4) Godfrey Memorial Library, comp.. American Genealogical-Biographical Index (AGBI) [database on-line]. Provo, UT, USA: Ancestry.com Operations Inc, 1999.
(5) Ancestry.com. Pennsylvania Pensioners, 1835 [database on-line]. Provo, UT, USA: Ancestry.com Operations Inc, 1998.
(6) Ancestry.com. Pennsylvania in the War of the Revolution : battalions and line, 1775-1783
(7) Index to the Chester County, Pennsylvania wills and intestate records